Fiat 500L Workshop Manual

Workshop Manual Autobooks Models Covered Fiat New 500 Fiat 500D Fiat 500F Fiat 500L Fiat and Autobianchi Giardiniera

Engine removal (station wagon) Engine disassembly (sedan—all versions) Engine disassembly (station wagon) Cylinder head removal, servicing and replacement Timing gear overhaul Crankcase and cylinders Piston assembly Connecting rods Crankshaft and main bearings 1 :1 Description The 'New 500' two-cylinder aircooled engine operates on the four-stroke 'Otto Cycle' and is fitted directly to the transmission unit which incorporates the rear drive assembly as shown in FIG 1 :1 and FIG 1 :2. With the power unit fitted at the rear several advantages are obtained including better load distribution to the wheels when the vehicle is loaded, elimination of propeller shaft reducing the size of centre tunnel and better use of available space. The cylinder block comprises two cast iron cylinder barrels with cooling fins. The bottom of the cylinders fit into machined seats in the aluminium crankcase. The aluminium crankcase carries eight studs on which are located the two cylinder barrels with the aluminium cylinder head on the top. A two bush crankshaft of special cast iron is fitted into the lower half of the crankcase. The crankshaft is F500 9 provided with a counterweight and is hollow to allow for lubrication. The steel connecting rods have thin wall bearing halves on the big-end, and bronze bushes in the small-end. The offset piston pin is of steel and retained in the piston by two circlips. Light alloy pistons are used and are of the taper-oval- shaped type with a maximum diameter at the base of the skirt, along an axis perpendicular to the piston pin. Pistons are fitted with four rings as follows, one compression at the top, two standard oil scraper rings and one side slotted oil scraper ring. The one-piece aluminium cylinder head is finned to provide a larger cooling surface and carries the inlet and exhaust manifolds. The inlet passages merge into a single centralized flange onto which is mounted the carburetter. The exhaust passages run almost parallel to the axis of the engine. 1 :12 1 :13 1 :14 1 :15 1 :16 1 :17 1 :18 1 :19 1 :20 1 :21 1 :22 Flywheel and starter ring gear The oil pump Lubrication, oil filter, relief valve Valve timing Valve stem to rocker clearance Engine assembly (sedan—all versions) Engine assembly (station wagon) Power plant mounting Adjustment of generator and fan belt drive Modifications Fault diagnosis

500 Sedan 10 FIG 1:2 Right side rear three-quarter view of the power plant for 500 Station Wagon Mounted on the top of the cylinder head is the overhead valve rocker mechanism that is operated by a chain driven camshaft through tappets and vertical pushrods. The carburetter is of the downdraft type fitted with a starting device that is controlled by a lever on the central floor tunnel. A pleated paper element air cleaner and silencer is fitted to the carburetter air intake. A mechanical diaphragm type fuel pump operated from the camshaft by a pushrod, supplies petrol to the carburetter from a fuel tank located at the front of the vehicle. Engine lubrication is provided by a gear pump driven from the camshaft and mounted within the timing cover drawing oil from the engine sump. The oil is cleaned by a centrifugal filter situated at the rear end of the crankshaft and pressure is controlled by a valve mounted on the pump body. Crankcase ventilation is provided for through a rubber hose connected to the top of the rocker cover. The engine is cooled by air from a centrifugal blower mounted on the generator shaft and housed in a specially designed cowling conveying air to and around the engine. The air temperature is governed by a special thermostat fitted in the engine cowling.

warmed air being ducted into the front compartment and controlled by a lever on the heating system tunnel. Engine ignition is by a battery, ignition coil and distribu- tor which is driven by a gear on the camshaft. The engine is started by an electric starter motor which is mounted on the gearbox casing and is controlled by a lever located behind the gearchange lever. The complete power unit is mounted by a spring support at the centre of the rear body crossmember and by two rubber pads mounted laterally to the gearbox. 1 :2 Engine removal (sedan—all versions) To remove the engine from the car proceed as follows: Raise the rear of the car and place on firmly based stands placed under suitable brackets on the underside of the body. Disconnect the battery positive terminal clamp from the battery terminal post. Release the clip securing the main petrol pipe to the tank sender unit and ease the pipe from the unit. Drain the oil from the engine sump into a suitably sized container. Disconnect the rear number plate light wire (see FIG 1 :6). Release the engine compartment lid check strap from its slot and separate the lid from the body by sliding the hinge apart. Remove the cables attached to the ignition coil, also to the generator and the starter motor. Remove the starter motor control tie rod. Release the oil pressure indicator cable, the main petrol pipeline at the pump, the accelerator and starting device controls. Remove the two hoses of the heating and cooling system which are the input hose to the blower and the hose for the car heating system. Release and lift out the engine apron. Remove the starter motor mounting bolts and carefully lift away the motor. Using a garage hydraulic jack with suitable cradle (see FIG 1:7) or a rope sling relieve the engine weight from its mountings. Remove the nuts securing the gearbox to the engine and the flywheel protection apron. Remove the bolts fixing the elastic support to the cross- member. Remove the rear crossmember mounting nuts noting that the engine earth cable is held by one mounting nut and lift away the crossmember. Carefully ease the engine away from the gearbox ensuring that there is no strain placed on the clutch shaft. Lower the engine to the floor taking care that no weight is allowed on any of the attachments. 1 2 3 4 5 6 7 8 1 :3 Engine removal (station wagon) To remove the engine from the station wagon proceed as follows: 1 Raise the rear of the vehicle and place on firmly based stands placed under suitable brackets on the underside of the body. 2 Disconnect the battery positive terminal clamp from the battery terminal post. Release the clip securing the main petrol pipe to the tank sender unit and ease the pipe from the unit. Drain the oil from the engine sump into a clean dry container of suitable size. 3 Hold the rear door open and secure using string to stop it swinging to the closed position. Secure the luggage compartment floor panel in its upright position. F500 13 4 Remove the cables attached to the ignition coil, also to the generator and starter motor. Remove the starter motor control tie rod. Release the oil pressure indicator cable, the main petrol pipeline at the pump, the accele- rator and starting device controls. Disconnect the air filter housing. 5 Remove the hose connecting the car heating system to the engine cowling. Disconnect the clip holding the air pipe to the blower and carefully disconnect the pipe from the blower cowling. Remove the starter motor mounting bolts and carefully lift away the motor. FIG 1:5 120.000 engine assembly: cross-section view through a cylinder

FIG 1:6 Engine compartment lid open LID LOCKING HOOK NUMBER PLATE LAMP CABLE NUMBER PLATE LAMP CABLE JUNCTION CROSS MEMBER ARR.2O74. FIG 1 :7 Engine removal using the jack with cross- member Arr.2074 6 Using a garage hydraulic jack with a suitable cradle relieve the engine weight from its mountings. Remove the nuts securing the gearbox to the engine. 7 Remove the nuts securing the rear bumper blade and panel to the body. Note that the engine earth cable is held by one mounting nut. Carefully dismantle the engine elastic mounting or release the bracket from the engine rear cover by removing the two nuts and washers. Lift away the rear panel assembly carefully making sure 14 FIG 1:8 Engine components: crankcase, cylinder head, timing sprockets cover To dismantle the engine proceed as follows: 1 Remove the exhaust silencer by releasing the two collars for attachment to the engine and the two con- nections for the exhaust pipe. It will be noted that there is one exhaust pipe connection on either side of the cylinder head. 2 Place the engine on a firm wooden top bench. Remove the two tappet cover retaining nuts and washers and lift away the cover. Remove the connection for cooling air delivery to the sump cooling ducts at the side of the sump. 3 Remove the air cleaner after first releasing the two bolts on the air cowling and the two nuts for the air elbow connection to the carburetter. 4 Remove the generator drive belt by releasing the three nuts so splitting the semi-pulley. Lift away the drive belt. 5 Remove all the bolts securing the air conveyor ducting to the cylinder head, to the crankcase and also to the engine cowling assembly opposite to the air conveyor. Release the accelerator control tie rod and carefully lift away the air conveyor assembly complete with the generator after first removing the clamp fixing the generator to the crankcase. 1 :4 Engine disassembly (sedan—all versions) that rear air ducting panels are not strained or the mating faces damaged. 8 Carefully ease the engine away from the gearbox ensur- ing that there is no strain placed on the clutch shaft. Lower the engine to the floor taking care that no weight is allowed on any of the attachments.

and lift away the distributor together with its support. 7 Remove all the mounting bolts of the engine cooling cowling and lift away the assembly. Release the two carburetter retaining nuts and carefully remove the carburetter together with its drip tray. 8 Lift away the valve rocker assembly having first released the two retaining nuts together with the plain washers and lock washers. Carefully lift out the valve rocker pushrods noting their relevant positions. 9 Slacken the four central cylinder head cap nuts and the four conventional nuts in the order, shown in FIG 1 :44 or 1 :46. Lift the cylinder head from the barrels. If difficulty is experienced it is essential to use Fiat tool A.40014 or a similar drilled plate, otherwise serious damage could be caused if other means are used (see FIG 1:9). 10 Remove the four pushrod sleeves and the casing containing the oil ducting to the overhead valve gear. 11 Remove the fuel pump retaining nuts and washers and lift away the pump. Carefully pull out the pump control pushrod from the crankcase. 12 Remove the six screws holding the centrifugal oil filter pulley cover and lift away the cover. Remove the centrifugal filter mounting flange by unscrewing the crankshaft central bolt. Also remove the timing cover containing the oil pump gears and the oil pressure regulating valve. Note the position of the nuts, toothed and plain washers for correct reassembly. 13 Release the four camshaft sprocket retaining bolts and lift away the sprocket and timing chain. Using Fiat pulley A.46020 or a large universal two-leg puller as shown in FIG 1 :10 remove the crankshaft sprocket and its body. 14 Carefully lift out the rocker pushrod tappets making a note of their location and gently pull out the camshaft making sure the front bearing bore is not damaged by the cam lobes or distributor drive gear. 15 Mark the flywheel and crankshaft to ensure correct reassembly and release the six flywheel retaining bolts together with the lockwashers and lift away the fly- wheel. 16 Using Fiat tool A.60156 on the two central studs, lock the two cylinder barrels in place as shown in FIG 1 :11. TOOL A. 40014 FIG 1:9 Tool A.40014 for cylinder head removal F500 15 17 Turn the engine upside down ensuring that no weight is placed on the studs and remove the oil sump and the oil suction scoop. 18 Mark the connecting rods and end caps to ensure correct reassembly and remove the end caps. Place the engine on its side and remove the cylinder barrels clamp. Ensure that the studs are clean and carefully slide off the connecting rod-piston-cylinder assem- blies from the crankcase. 19 Remove the six screws holding the rear main bearing housing to the crankcase and lift away the housing. Remove the six screws holding the front main bearing housing to the crankcase and lift away the housing. 20 Carefully ease the crankshaft from the crankcase moving it diagonally to assist withdrawal. FIG 1:11 Cylinder hold-down tool A.601 56 TOOL A.60156 FIG 1 :10 Removing crankshaft sprocket with puller A.46020 PULLER A.46020

A.40010 FIG 1 :13 Engine without blower cowling and cylinder head cover .SPACER AND CONNECTION FOR ROCKER SHAFT LUBRICATION TUBE OILVAPOR .VENT PIPE CASINGS FOR PUSHRODS (AND OIL RETURN TO CRANKCASE 21 To ensure no damage occurs to the long cylinder barrel mounting studs these may be removed using Fiat puller A.40010 or a universal stud removal as shown in FIG 1 :12. 1 :5 Engine disassembly (station wagon) To dismantle the engine proceed as follows: 1 Remove the exhaust silencer and manifold by releasing the four nuts holding the two flanges from the cylinder head. Also disconnect the two silencer mounting brackets and lift away the exhaust system (see FIG 1 :2). 2 Place the engine on a firm wooden top bench. Release the clip holding the tappet cover and lift away together with the drip tray. Disconnect the fuel line and throttle linkage at the carburetter and carefully lift away the carburetter together with its insulator joint and gaskets. 3 Remove the generator drive belt by releasing the three nuts so splitting the semi-pulley. Lift away the drive belt. 16 FIG 1 :14 Tool A.60084 for valve and valve spring removal TOOL A. 60084 4 Remove all the bolts securing the air conveyor ducting to the cylinder head and to the crankcase, carefully separate the panels and lift away the separate panels ensuring no damage is caused to the mating faces. 5 Release the ignition distributor retaining bolt and lift away the distributor. 6 Remove the fuel pump retaining bolts and also the three fuel pipe retaining clips and lift away the fuel pump assembly together with the insulator, gaskets and control rod. 7 Release the two valve rocker retaining nuts, note the order of assembly of washers and ease away the rocker shaft assembly from the top of the cylinder head. Carefully lift out the valve rocker pushrods noting their relevent positions for correct reassembly. 8 Slacken the four cylinder head cap nuts and the four conventional nuts in the order shown in FIG 1 :46. Lift the cylinder head away from the barrels. If difficulty is experienced it is essential to use Fiat tool A.40014 or a similar drilled plate as shown in FIG 1 :9, otherwise serious damage could be caused if other means are used. 9 Remove the four pushrod sleeves and the casing con- taining the oil ducting to the overhead valve gear. 10 Remove the six screws holding the centrifugal oil filter pulley cover and lift away the cover. Remove the centrifugal filter mounting flange by unscrewing the crankshaft central bolt. Also remove the timing cover from the rear of the crankcase. Note carefully the posi- tion of the nuts, toothed and plain washers for correct reassembly. 11 Release the four camshaft sprocket retaining bolts and lift away the sprocket and timing chain. Using Fiat puller A.46020 or a large universal two-leg puller as shown in FIG 1 :10 remove the crankshaft sprocket and its key 12 Carefully lift out the rocker pushrod tappets making a note of their location and gently pull out the camshaft making sure that the front bearing bore is not damaged by the cam lobes.

casting to the crankcase making a special note of the location of bolts of different lengths. 14 Mark the flywheel and crankshaft to ensure correct reassembly and release the six flywheel retaining bolts together with the lockwashers and lift away the fly- wheel. 15 Using Fiat tool A.60156 on the two central studs, lock the two cylinder barrels in place (see FIG 1 :11). 16 Turn the engine upside down ensuring that no weight is placed on the studs. 17 Mark the connecting rods and end caps to ensure cor- rect reassembly and remove the end caps. Place the engine on its side and remove the cylinder barrels clamp. Ensure that the studs are clean and carefully slide off the connecting rod-piston-cylinder assem- blies from the crankcase. 18 Remove the six screws holding the rear bearing hous- ing to the crankcase and lift away the housing. Remove the six screws holding the front main bearing housing to the crankcase and lift away its housing. 19 Carefully ease the crankshaft from the crankcase moving it diagonally to assist withdrawal. 20 To ensure no damage occurs to the long cylinder barrel mounting studs these may be removed using Fiat puller A.40010 or a universal stud remover as shown in FIG 1 :12. 1 :6 Cylinder head removal, servicing and replace- ment Description: The aluminium cylinder head is finned to increase the cooling surface. Through bolts secure the head and the two cylinders to the crankcase. The valves are controlled by a camshaft through tappets, pushrods and rockers. The connection between the head and the crankcase is via five sleeves mounted directly between the head and crankcase, and these accommodate the pushrods, lubricating oil and passage for the crankcase gases. The cylinder head has been modified for the 110 F and later 120 engines as they now incorporate a heater safety device as described in Section 4:4. FIG 1:15 Cylinder head 17 F500 The cylinder head should be removed whenever the valves require attention or the engine to be decarbonized. To remove the cylinder head proceed as follows: 1 Remove the air cleaner, carburetter, rocker cover and the screws securing the blower conveyor to the cylinder Removal of cylinder head: FIG 1 :17 Installing a valve guide using Tool A.60153 provided with pilot bush TOOL A. 60153- WITH PILOT BUSH FIG 1:16 Cleaning valve guides WIRE BRUSH A.11417 / BIS

head. Disconnect the two side exhaust manifolds. Note the spark plug HT cables locations and dis- connect from spark plugs. 2 Remove the rocker shaft pedestal- and lift away the rocker gear. Extract the pushrods, making a careful note of their location. Remove the cylinder head hold down nuts in the order shown in FIG 1 :44 and using a puller as shown in FIG 1 :9 lift off the head. Dismantling the cylinder head: 1 Using Fiat valve spring compressor A.60084 or a uni- versal spring compressor depress the valve spring as shown in FIG 1 :14 and lift out the cotters. Release the compressor and withdraw the lock cone, oil shield (inlet valve only) upper spring cup, valve spring and lower spring cup. Withdraw the valve from the under- side of the head. 2 Dismantle the remaining three valve assemblies as detailed above ensuring that all parts are kept in sets for correct reassembly. Inspection and servicing of the cylinder head : 1 Remove all carbon deposits from the combustion chambers and valve ports using a rotary wire brush or a set of scrapers. 2 Thoroughly clean the cylinder head and to test for dis- tortion lightly coat the machined faces with 'Engineers Blue' or lamp black and place the cylinder head on a surface plate. Carefully slide to and fro and any streaks left behind will indicate a distorted surface. A distorted head will not make a gas-tight seal with the cylinders and must be entrusted to an expert for correction or, in severe cases, renewed. 3 Carefully clean the valve guides as shown in FIG 1:16 using Fiat guide brush A.11417 bis. Should the guides 18 Reassembly is the reverse procedure to dismantling. During assembly utmost cleanliness must be observed as any abrasive material could find its way to the pistons and cylinder bores causing unnecessary wear. Check that the cylinder barrel mating face is clean to ensure correct gasket sealing. Reassembly of the cylinder head: be worn then they should be removed using a press and a suitable sized drift. The guides are press fitted with a pinch fit of .00134 to .00244 inch. To install the guides use Fiat tool A.601 53 as shown in FIG 1 :17. As the guides have no stop ring during the press fitting, the depth of insertion is determined by the Fiat tool. If the tool is not available take the necessary depth measure- ments before the old guides are removed. The normal fit clearance between valve stem and guide is .00087 to .00217 inch with a maximum wear limit of .0059 inch. To check this see FIG 1:18. 4 The valve seats should always be reconditioned after decarbonization. It is suggested that this operation be left to a local service station with valve seat cutting equipment. The valve seat angle for both inlet and exhaust valves is 45° ± 5'. 5 Inspect the valves for soundness or distortion and if the clearance between guide and stem is within the manu- facturers wear tolerance of .0049 inch the valve may be cleaned using a wire brush and the seating face ground to an angle of 45°30' ± 5'. This again should be left to the local service station. Valve springs: Thoroughly clean the valve springs of oil deposit and inspect for cracks. It is advisable to check the free spring height and if this dimension differs from the original height, details of which are given in Technical Data, the spring must be renewed. Any decrease in length indicates that the spring has weakened.

To refit the cylinder head proceed as follows: Place a new cylinder head joint on the cleaned faces of the cylinder barrels. Insert the rocker pushrod and lubrication pipe sleeves together with the relevant gaskets and rings. Fit the washers and nuts to the studs and tighten to fingertight. Tighten the nuts in the order shown in FIG 1 :44 and FIG 1 :46 to a torque wrench setting of 18.1 Ibft. Reset the torque wrench to a new setting of 23.9 Ibft and tighten the nuts once more in the recommended order. Replace the pushrods in the correct order. Refit the rocker shaft ensuring correct location of the lubrication tube to the rocker shaft and replace the plain and lockwashers. Tighten the nuts to a torque wrench setting of 15.2 Ibft. Reset the tappet to rocker clearance adjustment. Connect the two exhaust side manifolds to the cylinder head. Using new gasket refit the spark plugs and HT cables. Replace the rocker cover fitted with a new cork gasket and blower conveyor to the cylinder head securing screws. Refit the carburetter and reconnect its fuel line and controls. Refit the air cleaner and elbow and connect the rocker cover breather pipe (if fitted). 1 2 3 4 5 1 :7 Timing gear overhaul Camshaft: The cast iron camshaft is located in the crankcase and is supported at either end in sets machined directly in the crankcase. No bushes are used. The camshaft is driven by a chain from the crankshaft at half engine speed and operates the overhead valves through tappets, pushrods and rockers (see FIG 1 :20). During engine overhaul the camshaft journals and cam faces should be free of score marks or signs of seizure and have a bright mirror finish. The distributor drive gear should be inspected for tooth wear which if excessive means that the camshaft must be replaced. Tappets: The tappets should be inspected for signs of seizure or excessive wear. The end surface that is in contact with the camshaft should be smooth without signs of excessive wear. Any slight scratches or indentations may be removed using a very fine oil stone. Pushrods and sleeves: The pushrods operate in special axially resilient sleeves that are compressed on assembly between the cylinder head and the crankcase. It is through these sleeves that the engine sump is vented also through which the oil returning from the cylinder head passes. Two rubber O-ring seals are fitted to each sleeve to ensure an oil tight seal between the cylinder head and crankcase. The sleeves should be checked for distortion and exact equal length and when refitting new seals must always be fitted. The pushrods should be checked for straightness and the two ends that contact the rocker setscrew and the F500 19 The crankcase is an aluminium casting suitably ribbed to ensure correct air cooling. The main bearing and cam- shaft bearing bores are machined as also are the tappet 1 :8 Crankcase and cylinders During valve gear overhauls the clearance between the rocker shaft bore and the rocker must be checked. The maximum permissable wear between these two parts is .0059 inch. It is recommended that the part which is most worn be renewed, or in extreme cases both parts. Rocker and rocker shaft: tappet seat must not show any signs of roughness or excessive wear. 3 Oil shield (for intake valves only) 4 Snap ring 5 Rocker 6 Upper spring cup 7 Valve spring 8 Lower spring cup 9 Pushrod 10 Tappet 11 Oil seal ring 12 Pushrod sleeve 13 Seal ring 1 Intake valve 2 Upper cup lock Key to Fiq 1 :20 FIG 1:20 Valve, pushrod and tappet assembly FIG 1:19 Camshaft. The arrow points to the lube oil outlet port

indicates the class to which cylinder belongs, as referred to its inside diameter CLASS LETTER FIG 1 :22 Cylinder measurement points seats, gearbox companion flange and timing gear cover mounting flange. The cast iron cylinders are finned radially to increase the cooling air surface and are located symmetrically on the crankcase, each being held by four studs. The cylinders are installed by sliding into the crankcase bores and finally held in place by the cylinder head (see FIGS 1 :8 and 1 :21). Inspect the cylinder bores for score marks, wear and any other defects or damage. The clearance between the piston maximum diameter and the cylinder bore should be checked to ensure that it is within the maximum wear limit of .0059 inch. 20 FIG 1 :23 Checking cylinder diameter by dial gauge C.687 brought to zero with ring gauge C.672 DIAL GAUGE C 687 RING GAUGE C. 672 The cylinder height must be checked between the seat- ing face on the crankcase and the top surface and this dimension should be 3.5433 ±0 0 0 6 inch. If this dimension is less than specified the cylinder must be renewed to prevent possible carbon deposits on the piston crown and underside of combustion chamber causing the piston to strike the cylinder head (see FIG 1 :24). Checking cylinder height: This operation should bring the bore size to correspond to the oversize piston sizes in order to obtain the correct clearance between the piston and cylinder. These limits are given in Technical Data. It will be observed that the cylinders are divided into three classes depending on the bore diameter. The classes are identified by the letters 'A', 'B1 and 'C, one of which will be stamped on the mating face with the cylinder head as shown in FIG 1 :21. Pistons are divided into three classes to correspond with the cylinder bore sizes. Naturally the piston and bore must belong to the same class. The maximum available piston oversize is .0236 inch. Pistons and rings for the Model 500 sports engine are not available in oversize dimensions so if the cylinder bore diameter is above the maximum wear limit new parts must be fitted. Honing or reboring cylinder bores: It is essential that the diameter measurements are taken at two different heights in the cylinder bore along both the longitudinal and transverse axles as shown in FIG 1 :22. It is recommended that to zero the internal micrometer Fiat ring gauge C.672 is used (see FIG 1 :23). If bore wear or ovality is between .0059 and .0079 inch the cylinder bore may be honed. Should however the wear limit of .0079 inch be exceeded then the bores must be recut.

between the crankcase and cylinder bottom face and a .0236 to .0275 inch thick graphitized asbestos gasket between the cylinder and cylinder head. The compression of the gaskets on assembly will eliminate any very small differences between the two mating surfaces. Inspection of tappet seats: The tappet seats should be checked for scoring and correct clearance which must not exceed .00315 inch. Should the clearance be greater than the maximum specified the seating may be reamed to oversize dimen- sions as detailed in Technical Data. Tappets are avail- able in .00197 and .00394 inch diameter oversize. 1 :9 Piston assembly Inspection: Before inspection the pistons must be thoroughly cleaned and the ring grooves and piston head decarbo- nized. Check for deep score marks and signs of distortion or fracture especially around the skirt and piston pin areas. Using a feeler gauge ensure that the piston clearances in the bore do not exceed a maximum of .0059 inch for the Model 500 engine and .0079 inch for the Model 500 sports engine (see FIG 1 :25). The measurements should be taken at the bottom of the skirt and square to the piston pin axis. Should the clearance be greater than the maximum permissible, the cylinders may be rebored and oversize pistons fitted to match them. Pistons are supplied in the following oversizes, .0079, .0157 and .0236 inch. It should be noted that oversize pistons and rings are not available for the Model 500 sports engine so if the piston to cylinder wall clearance is greater than the permissible maximum limit the cylinder and piston assembly must be renewed. The piston ring to groove clearance must be checked as shown in FIG 1 :26 and the ring gap when fitted as in FIG 1 :27. In both cases the readings should be compared with the piston data. Piston rings are available in the same oversize classes as the pistons. When installing piston rings the gap should be placed opposite to the piston expansion stops. Ensure that the ring gaps are scattered and not in a line. FIG 1:24 Checking cylinder head mating face for level Out-of-true should not exceed .00315 inch F500 21 The installation of the piston and connecting rod should be carried out on a clean workbench as shown in Reassembly of piston: Check that the fit between the piston pin and boss is a pinch fit. If excessive clearance is found the boss may be reamed and a .0079 inch diameter oversize piston pin fitted. The pin to bore pinch fit must be between .0000 to .0039 inch. At all times the pins should be installed only after the piston has been heated in hot water to a tempe- rature of 80°C. Upon reassembly of the piston to the engine the expansion slot must be placed facing the cam- shaft. FIG 1 :26 Checking piston ring-to-land clearance FEELER GAUGE C.316 FIG 1:25 Using feeler gauge C.316 to check piston-to- cylinder wall clearance

FIG 1 :27 FIG 1 :28. A universal piston ring compressor should be used to keep the rings tight in their grooves. The correct matching of the piston and connecting rod is described in a later section of this chapter. 1 :10 Connecting rods Checking rod bearing inserts and crankpin jour- nals: The big-end bearing halves are of the babbit lined thin wall type and must not be modified in any way. Should score marks or excessive wear be evident the bearing inserts must be renewed. It is recommended that if the bearing inserts are to be renewed due to wear the crank- pins should be measured to see if regrinding is required. Before regrinding the crankpins they should be measured at the maximum point of wear to determine the class of bearing undersize to be fitted after regrinding the crankpins. Undersize bearing halves are available in the following sizes .01, .02, .03 and .04 inch. The correct bearing crankpin clearance is .00043 to .00240 inch and must be checked as detailed in the following section. Checking rod bearing insert to crankpin journal clearance: Before the crankshaft is installed into the engine after overhaul the clearance must be checked to ensure that it is within the manufacturers recommended limits. To check the clearance proceed as follows: 1 2 Lubricate the crankpin and bearing inserts and install the connecting rod together with its bearing halves on the crankpin. Tighten the cap nuts to a torque wrench setting of 23.9 Ibft. Rotate the connecting rod around the crankshaft jour- nal several times to seat the bearing insert correctly. Remove the bearing end cap and carefully wipe away all traces of the lubricant. 22 FIG 1 :29 Connecting rod components Piston installer A.60154 FIG 1 :28 PISTON INSTALLER A. 60154 If the clearance indicated is within the recommended FIG 1 :31. 4 Place a piece of 'Plastigage type PG-1' along the full width of the bearing insert along the crankshaft longitudinal axis (see FIG 1 :30). Refit the bearing cap and tighten the nuts to a torque wrench setting of 23.9 Ib ft. Remove the bearing cap and upon inspection the 'Plastigage' will be found to have adhered to either the crankpin or bearing insert and will have developed a rectangular section. To determine the actual clearance between the crankpin and bearing insert compare the width of the flattened 'Plastigage' at its widest point with the graduations on the envelope as shown in 3 PISTON RING

.0059 inch the bearing inserts may be used again with- out any need for regrinding. Should however the clearance be greater than .0059 inch the inserts must be renewed, using undersize inserts if the crankpin journals have been reground. It should be observed that 'Plastigage PG-1' is suitable for measuring clearances up to .0030 inch so that if carrying out 3 above produces no flattening of the 'Plastigage' the procedure must be repeated using 'Plastigage PR-1' which enables clearances up to .0060 inch to be measured. 5 CRANKSHAFT CON ROD CALIBRATED STRIP CON ROD BEARING CAP BEARING INSERT FIG 1:30 'Plastigage' position for bearing insert-to- crankpin journal clearance inspection GRADUATION SCALE BEARING .INSERT CLEARANCE READING CALIBRATED STRIP CON ROD BEARING CAP FIG 1 :31 Checking bearing insert-to-crankpin journal clearance by comparing width of flattened 'Plastigage' F500 23 To fit a replacement bush proceed as follows: Firmly hold the connecting rod between soft faces in a vice in such a way that it will not bend when working on the small-end and using a suitably sized drift, remove the old bush. Use Fiat tool A.60155 or a suitably sized drift and care- fully install the new bush which must be an interference fit of between .0011 to .0036 inch. A small slot must be cut in the bush to correspond with the groove machined at the top of the connecting rod so ensuring good lubrication between the bush and piston pin. 1 2 3 The small end bush must be a firm fitting in the con- necting rod and show no signs of deep scoring, scuffing, ovality or excessive wear. Should it be considered necessary, the bush may be reamed using a Fiat expanding reamer U.0307 so that the bush internal diameter permits an oversize piston pin to be fitted with a clearance of .00020 to .00063 inch. Little end bushing: Installation of connecting rod bearing inserts: During reassembly of the big-end bearing inserts the parts must be thoroughly cleaned and then to reassemble proceed as follows: Ensure the bearing half to connecting rod surfaces are perfectly smooth and free of score marks. Under no circumstances may the bearing surface be reworked. Check that the bearing half inserts are properly seated, with the locating lugs fitting into their slots: this is essential to obtain correct bearing clearance. As the circumference of the bearing half is greater than the seats in connecting rod and cap the bearing must be fitted so that the projection at each end of the bearing half is equal. Thoroughly lubricate all parts and tighten the end cap nuts to a torque wrench setting of 23.9 Ib ft. 1 2 3 4 FIG 1:32 Connecting rod-piston assembly installation on engine REVOLUTION DIRECTION PISTON SLOT CAMSHAFT CONNECTING ROD NUMBER

shoulder clearance FIG 1:34 Engine front end without flywheel Using an expanding reamer or Fiat reamer U.0307 ease out the internal diameter of the bush to between .7874 to .7876 inch so that a standard piston may be fitted. 4 Piston-connecting rod assembly: To assemble the piston to the connecting rod fit the connecting rod to the piston so that the cylinder identifica- tion number which is stamped on the connecting rod stem and cap faces the expansion slot side in the piston as shown in FIG 1 :32. Lubricate the piston with engine oil, compress the piston rings into their grooves and insert the piston con- necting rod assembly into the cylinder barrel with the identification numbers facing to the side opposite to the camshaft as shown in FIG 1 :32. If one or both connecting rods have been renewed the new connecting rod cap and body must be stamped with the cylinder identification number. The figures should be stamped as shown in FIG 1 :32. 24 FIG 1:35 Camshaft end crankshaft supporting mem- ber and bearing assembly, and spare main bearing CRANKSHAFT SUPPORTING MEMBER (Camshaft end) MAIN BEARING Carefully inspect the crankshaft for minute cracks espe- cially where there is a change in section. Should there be any doubt always consult the official agents for further advice. Inspect the journals and crankpins. Should score marks or ovality exist on the journals or crankpins they must be reground and new undersize bearings fitted. Undersize main bearings are obtainable in the sizes .0079, .0157, .0236, .0314, .0394 inch ready fitted in supports. Undersize connecting rod bearings are obtainable in the sizes .01, .02, .03 and .04 inch. The crank should be reground to match the appropriate bearing undersize. The clearance between the main bearing to journal should be .00079 to .00256 inch and the connecting rod bearing half to crankpin between .00043 to .0024 inch. 2 1 The special cast iron crankshaft is hollow to allow for the passage of lubrication oil. It is supported at its ends and is provided with two cranks and a central counterweight. The crankshaft plays an important part in the operation of the lubrication system as its cavity provides a passage for the oil flowing from the centrifugal filter. Before inspecting the crankshaft thoroughly clean the internal passage and drillings as well as the exterior and then proceed as follows: 1:11 Crankshaft and main bearings Upon reassembly the connecting rod cap nuts must be tightened to a torque wrench setting of 23.9 Ib ft.

that all traces of swarf are removed by constant washing and then drying with a non-fluffy rag. The clearance between the main bearings and journals must be checked before installing the crankshaft in the engine. It should also serve as a recheck after the crankshaft has been reground. Measure the maximum main bearing internal diameter and the minimum journal diameter using accurate measuring equipment. The clearance must not exceed .0039 inch otherwise the journals must be reground and undersize bearings fitted. Undersize bearings with .0394 inch stock on the internal diameter are also supplied unmounted. They must be press fitted in the supports, the recommended interference fit being .00039 to .00197 inch. After pressing the bearing into the support, a hole is drilled in the bearing in line with the location dowel hole in the support. The hole is finished with a suitable expanding reamer, such as Fiat U.0334, and the dowel pressed in, noting that the hollow dowel fits in the flywheel end support. The next stage is to heat the assembly in an oven or oil bath for a period of one hour at 150°C (302°F). When the assembly has cooled to room temperature, the bearing is reamed in a lathe to match the crankshaft journal size. 3 Crankshaft oil seals: Two inner spring rubber oil seals are located, one in a special seat in the timing gear cover and the other in the flywheel end of the crankshaft support and provide oil tightness. These seals are shown in FIGS 1 :3 and 1 :34. Whenever the engine is dismantled for overhaul these seals should be carefully inspected for correct seating and that the inner seal surface is not worn and that the contact area is perfect both on the crankshaft and on the fan and generator drive pulley hub. Clutch shaft pilot bushing: A self-lubricating bronze bush is fitted in the end of the crankshaft as shown in FIG 1 :34 and provides a bearing for the clutch shaft. Should the bush be worn use Fiat puller A.40006/1 /2 to remove the worn bush. A new bush should be fitted using a suitably sized drift. 1:12 Flywheel and starter ring gear The flywheel should be inspected for wear at the clutch driven plate contact area. It should be flat and have a smooth finish. The ring gear teeth should be cheeked for damage which if evident, the ring gear must be replaced. To facili- tate the fitting of a new ring gear on the flywheel, the new ring gear should be heated in an oil bath to a temperature of 80°C (176°F). Using a press gently ease the expanded ring gear over the flywheel and press fully home. 1:13 The oil pump Sedan : A helical-spur gear type oil pump is driven by the cam- shaft through a front dog drive coupling. The gears are F500 25 To remove the pump from the engine proceed as follows: Pump removal and reassembly: Remove the engine rear central support from the timing gear casing. Remove the filter cover pulley and lift away the drive belt. Release the hollow screw attaching the slinger and the mounting flange of the filter on the crankshaft. Also release the nuts fixing the timing gear cover to the crankcase. Remove the timing gear cover together with the oil pump assembly and the pressure relief valve. Lift out the oil pump suction scoop with the filter screen attached from the sump. Reassembly of the pump to the engine is the reverse procedure to dismantling. 1 2 3 4 5 located in a special housing in the timing gear cover and held in place by a cover plate. The oil pressure relief valve is mounted on the drive gear shaft guide. A pump suction scoop fitted with a filter screen is secured in the crankcase and connects to a duct in the timing gear case as shown in FIG 1 :36. 2 4 6 Key to Fig 1 :36 Rocker shaft Ducts, cylinder head oil drain Oil pressure relief valve to centrifugal filter 9 with central oil gallery 12 Sump cooling air conveyor indicator sending unit Oil filler with vent valve Line, oil delivery to rocker shaft Level indicator rod 3 1 5 7 Gear pump 8 Oil duct Centrifugal oil fitter 11 10 Crankshaft Oil pump intake screen filter 13 Low oil pressure FIG 1:36 Engine lubrication diagram

Key to Fig 1:37 1 Oil dipstick 2 Oil filler with vent valve 3 Centrifugal oil filter 4 Crankshaft, with central oil gallery 5 Low oil pressure indicator sending unit 6 Oil pressure relief valve 7 Gear pump 8 Camshaft, with central oil gallery 9 Oil suction filter from sump 10 Oil sump drain plug 11 Oil delivery line to rocker shaft 12 Rocker shaft 13 Head cover Pump dismantling, inspection and reassembly: Remove the lock ring and withdraw the pressure relief valve and spring. Remove the oil pump cover plate and ease out the gears and shaft. Thoroughly clean all the parts and blow clean using a compressed air jet. Inspect the timing gear cover for cracks or distortion. Check that the inner duct for oil delivery to the pump is clear of obstruction. Use a compressed air jet to clean the passage. Check the oil pump gear teeth for damage or excessive wear and fit new gears if necessary. The recommended backlash is .0059 inch with a maximum wear limit giving a backlash of .0079 inch. Check the clearance between the gear teeth and the housing walls in the timing gear cover. The recommended clearance is .0012 to .0035 inch with a maximum of .0047 inch. Ensure that the drive gear is firmly attached to its shaft. Upon assembly there is a pinch fit of .0016 to .0031 inch between the two parts. The driven gear to shaft clearance upon assembly is .00079 to .00236 inch with a maximum wear limit of .0039 inch. Also check the width of the drive and driven gears which when new should be .3937 to .3928 inch with a minimum width of .3917. In service a spare drive gear is supplied complete with its shaft. 26 4 3 2 1 Station wagon: A helical-spur gear type oil pump is driven from the lower end of the distributor drive spindle which is in mesh with the camshaft. The gears are located in a special housing in the bottom of the timing gear housing and are held in place by a cover plate. The oil pressure relief valve is located at the driven end of the camshaft. A pump suction oil filter is fitted in the sump and this connects to a duct in the timing gear case so supplying oil to the pump (see FIG 1 :37). Pump gears removal, inspection and reassembly: To remove the pump gears from the timing gear cover proceed as follows: Inspect the filter screen on the end of the pump suction scoop and remove any obstruction. If the screen is damaged it must be renewed. Check that the pump drive dog is a good fit on the cam- shaft and that the dogs are not badly worn so as to impair the pump operation. Reassembly of the pump is the reverse procedure to dismantling. Ensure that the pump cover piate is correctly located by means of the dowel on the timing gear cover. 5 6 7

out. Thoroughly clean the area around the pump body (see FIG 1 :37). Remove the end cover plate by releasing the retaining bolts and washers. Carefully ease the driven gear down- wards followed by the driving gear and shaft Clean all parts removed and blow clean using a com- pressed air jet. Inspect the timing gear cover pump area for cracks or distortion. Check that the inner duct for oil delivery to the pump is clear of obstruction. If in doubt remove the drain plug and filler cap and use a com- pressed air jet to clean the passage. Check the gear teeth for damage or excessive wear, ensure that the drive gear is firmly attached to its spindle and that the end cover plate is not badly scored or pitted. Fit new parts as necessary. Reassembly is the reverse procedure to dismantling, taking care that all parts are assembled clean and the end cover plate seating correctly with a new gasket. 5 4 3 2 1 1:14 Lubrication, oil filter, relief valve Description : The engine is pressure lubricated through a gear type pump which is incorporated in the timing gear cover and driven from the camshaft by dogs or gears. The lubrication circuits are shown in FIGS 1 :36 and 1 : 37. The pump draws oil from the sump through a suction horn fitted with a filter screen which is fixed to the crank- case by a duct in the timing gear cover. This supplies oil to the pump. Oil passes from the camshaft rear seat onto the crank- shaft rear support where it flows into an adjacent chamber. From here the oil flows through ducts in the crankshaft from end to the centrifugal oil filter. The centrifugal filter, which also acts as a pulley for the generator and blower drive, rotates with the crankshaft. Oil from the filter enters a passage in the crankshaft, where it lubricates the main and connecting rod bearings and passes from a special groove in the front main bearing and ducting in the crankcase into which is inserted the oil pressure warning sender unit, and also the delivery pipe for oil to the overhead valve gear. The pushrod sleeves provide the return path for the oil from the cylinder head and delivers oil to the tappet gear and the camshaft cams. The tappets are suitably drilled to allow correct circulation of the oil. The tappets are located in two casting cavities, one of which com- municates with the timing gear housing and the other one to the crankshaft front drain support drain. The oil pressure is regulated by a pressure relief valve 5 (see FIG 1 :38) mounted at the rear end of the camshaft. It comprises a hubbed disc which slides on a guide 6 of the oil pump drive shaft 7. Under spring load 9 the valve disc circumferentially closes an annular chamber which communicates with the lubrication circuit. Excessive oil pressure causes the disc to uncover the chamber. Centrifugal oil filter: The oil filter is of the centrifugal type comprising of two flanges and an oil slinger. The filter is attached to the rear end of the crankshaft as shown in FIG 1 :38. The outside diameter of the oil slinger (see FIG 1 :39) is smaller in diameter than that of the flanges but of such a F500 27 Key to Fig 1:39 1 Drive pulley 2 Rotor hub 3 Seal ring 4 Oil slinger 5 Lockplate 6 Hub-to-crankshaft hollow screw 7, 8, 9 Pulley-to-hub mounting screws, toothed washers and plain washers FIG 1:39 Centrifugal oil filter components Key to Fig 1 :38 Suction scoop 2 Hole in crankcase 3 Duct in timing sprocket cover 4 Timing sprocket cover 5 Oil pressure relief valve 6 Drive shaft guide and oil pump cover 7 Oil pump driving gear shaft 8 Camshaft 9 Oil pressure relief valve spring FIG 1:38 Engine longitudinal section through oil pump

Engine detail showing lube oil passages Key to Fig 1 :40 1 Splines in crankshaft for oil passage to filter 2 Oil inlet into circuit from filter 3 Hole for oil passage to main bearing FIG 1 :41 Timing marks on sprockets. On later cars the crankshaft key way is on the underside size that centrifugal force does not sling oil into the area where the foreign matter is collected. The outer flange inner face has radial vanes on its face which retain the foreign matter and the oil is conveyed to the centre of the filter. The oil to be filtered issues from the side splines 1 (see FIG 1 :40) of the crankshaft and is forced by the slinger to the periphery of the filter where it is cleaned and returns to the centre of the filter and into the crankshaft drilling 2. The inner flange or hub and the slinger are secured to the crankshaft by a special hollow screw 6 as shown in FIG 1 :39, the outer flange is attached to the hub by six screws. 28 If the camshaft has been disconnected from the crank- shaft for any service operation the valve gear will have to be retimed and to do this proceed as follows: 1 Turn the crankshaft until the reference line on its sprocket is pointing towards the camshaft as shown in FIG 1 :41. 2 Turn the camshaft until the reference dot on its sprocket registers with the crankshaft sprocket. Leave the shafts undisturbed and carefully mount the chain. Should it be necessary to check the valve timing and sprocket marks, proceed as follows: 1 Fit Fiat C.673 tool as shown in FIG 1 :42. 2 Temporarily adjust the valve stem-to-rocker arm clearance of cylinder No. 1 at .01 77 inch for the inlet valve and .01 50 inch for the exhaust valve (Model 500 engine) or at .01 54 inch for both valves (Model 500 sports). 3 Rotate the crankshaft and set the flywheel timing mark at 'O' on the graduated sector. Check that the sprocket marks are correctly lined up in this position. If the engine is being assembled, to install the driven gear, proceed as follows: 1 Set the timing mark on the drive sprocket towards the centre of the camshaft. 2 Position the driven sprocket on the camshaft mounting flange with four screw holes in line and tighten two mounting screws only. 3 Rotate the camshaft until the driven sprocket mark registers with the reference line on the drive sprocket. 4 Remove the driven sprocket without moving the camshaft. Install the timing chain and replace the driven sprocket. Tighten the four screws to a torque wrench setting of 6.5 Ib ft. 1:15 Valve timing The oil pressure indicator sender unit is located on the righthand side of the cylinder block and is connected to an indicator light in the instrument cluster on the dash- board. The red indicator lights only when the ignition is switched on and goes out when oil pressure has built up to between 8.5 and 14 Ib/sq in. Should an accidental shortcircuit occur in the oil pressure indicator circuit, the sender unit may be damaged so the cause must be traced and rectified before the unit is renewed. Oil pressure indicator sender unit: To ensure a reliable lubrication system there must be no oil leaks from the gasket between the outer and inner flanges. Every time the engine is overhauled the filter must be dismantled, cleaned and new gaskets fitted. To clean the filter, remove the six screws and washers and separate the drive pulley and hub. Carefully scrape the inner surfaces to remove all sludge. Upon reassembly the filter to crankshaft hollow mounting screws must be tightened to a torque wrench setting of 1 08.5 Ib ft. The cover to mounting flange screws must be tightened to a torque wrench setting of 5.8 Ibft. Cleaning and inspection: A groove is machined on the outer flange periphery to form a pulley for the generator and blower drive belt.

timing angles are as detailed in Technical Data. Readjust the valve stem to rocker arm clearance to the correct setting. 1:16 Valve stem-to-rocker clearance adjustment It is important that the clearance between the valve stem and rocker is kept to the recommended figure of .0059 inch, measured when the engine is cold. If the clearance is excessive operating noise will occur and if less than recommended the valves will stay open too long which will result in damage to the valve face and its seating. Inspect the contacting surfaces for scoring or pitting: if it is excessive, new parts must be fitted. Also check the condition of the rocker-to-valve and rocker ball head-to-pushrod contact surfaces are free from wear or pitting. The faces must have a mirror finish. The oilway in the rockers and shaft must be thoroughly inspected and free from sludge, otherwise lubrication failure will occur. The assembly clearance between the rocker arm and shaft should be .00063 to .00217 inch and the clearance between the rocker shaft and the shaft support should be .00020 to .00138 inch with a maximum wear limit of 0039 inch. Turn the engine until the valves of one cylinder are in balance, that is, the inlet valve opening and the exhaust valve closing. The other cylinder will now have both valves fully closed. Adjust the valves on this second cylinder by loosening the locknut, and turning the adjuster as shown in FIG 1 : 43 to obtain the desired clearance measured with a feeler gauge. Adjust the clearances on the other cylinder in the same manner. 1 :17 Engine assembly (sedan — all versions) To reassemble the engine proceed as follows: 1 Thoroughly clean and dry all the parts, ensure that all drillings are free from dirt or sludge and place on a clean dry surface. 2 Carefully install the cylinder-piston-connecting rod assemblies with new paper gaskets between the cylinders and crankcase seats. 3 Refit the big-end bearing shells to the connecting rods, ensuring that they are free from any dirt or metallic particles. Carefully ease the crankshaft into the crankcase, lubricate the main journals with clean engine oil, place a new paper gasket between the supporting member and the flywheel end of the crankcase. Install the supporting member and bearing assemblies. Secure the supporting members with the screws and special toothed washers. 4 Locate the connecting rod big-end half onto the crankpin journals, liberally lubricate the journals with fresh engine oil, fit the remaining shell half, matching bearing end cap and tighten the bearing cap nuts to a torque wrench setting of 23.9 Ib ft. 5 Inspect the camshaft bearing bores and remove any burrs with a hand scraper wetted with oil. Carefully slide in the camshaft ensuring the cam lobes or gear teeth do not score the front bearing bore. 6 Fit a new timing gear cover paper gasket held in place with a little grease. Install the outer thrust ring, F500 29 inner thrust ring, shoulder washer and slide on the camshaft drive sprocket, locking it with the Woodruff key. Assemble the timing chain and driven sprocket, ensuring that the timing marks on the sprocket are indexing as shown in FIG 1 :41. Secure the driven sprocket with six screws and lockplates and care- fully bend down the lockplates. 7 Install the timing gear cover, the oil pump, oil pressure relief valve and seal assembly. Secure with nuts, special toothed washers and plain washers located in the same manner as was noted on dismantling. Locate the oil pump suction horn and secure with the nuts and toothed washers. 8 Install the flywheel in the same relative position to the crankshaft as was noted on dismantling. Replace the FIG 1 :43 Adjusting the rocker clearances using the optional service tools. Refer to Technical Data for the correct clearance on early and late engines FIG 1 :42 Graduated sector C.673 for valve gear timing TIMING MARK

Cylinder head hold-down nuts tightening sequence. 500 Sedan TIMING CHAIN END CYLINDER No. 1 CYLINDER No. 2 FLYWHEEL END CAMSHAFT EXPANSION SLOT C/ROD NUMBER ROTATION DIRECTION FIG 1 :45 The correct position of connecting rod- piston assembly on engine 120.000 30 screws and together with new lockplates tighten to a torque wrench setting of 23.1 Ib ft. Bend down the lockplates. 9 Slide the centrifugal oil filter mounting flange, the oil slinger and the mounting screw together with its lockplates onto the crankshaft and tighten the screw to a torque wrench setting of 108.5 Ib ft. Bend down the lockplate. 10 Assemble the clutch assembly to the flywheel and using Fiat pilot A.62023 centralize the driven plate to the pressure plate assembly. Secure the pressure plate assembly using screws and toothed washers. 11 Fit new oil pan cork gasket, if necessary using a little grease to hold in position and carefully fit the oil pan securing with screws, toothed washers and lock- plates. Bend down the lockplates onto the screw heads. 12 Fit the oil cooling air conveyor on the oil pan and secure with screws and toothed washers. 13 Carefully turn the engine over and fit the centrifugal filter mounting flange rubber seal. Fit the oil filter cover and secure with screws together with plain and toothed washers to a torque wrench setting of 5.8 Ib ft. 14 Ensure the faces of the cylinder head and cylinders are free from dirt and oil and carefully slide the cylinder head gasket over the studs ensuring that it is the correct way up. Insert the tappets in the same order to removal together with the sleeves, pushrods, oil delivery line to the rocker arm shaft and the casing with its seal ring. 15 Thoroughly inspect the cylinder head to ensure that it has been correctly reassembled, carefully slide it over the studs and secure using the four cap nuts internally and four standard nuts and plain washers externally. Tighten the nuts in the order as shown in FIG 1 :44 or 1 :46 to a torque wrench setting of 23.9 Ib ft. 16 Fit the rocker arm shaft and arm assembly together with the two supports. Tighten the supports using screws, plain and toothed washers to a torque wrench setting of 15.2Ibft. Adjust the tappet-to- rocker clearance as detailed in Section 1 :16. 17 Temporarily plug the intake duct hole to ensure that no foreign matter finds its way into the engine. Install the spark plugs having ensured that they are clean and correctly adjusted. 18 Reassemble the engine cowling and air exhaust throttle valve assembly which should be secured on the top side using two nuts, two plain washers and two toothed washers, on the underside with two screws and two toothed washers, and centrally using one screw and one spring washer. 19 Fit the toothed washers on the end of the spark plug electrode and tighten the terminals together with the special rubber boots. 20 Refit the fan, generator and ground cable assembly and secure the crankcase, also the warmed air intake shrouding. Finally tighten the generator to fan nuts. 21 Fit both lower exhaust silencer mounting brackets onto the crankcase but do not tighten fully. Fit the air conveyor and secure to the engine cowling using six screws, six toothed washers and one nut together with a toothed washer. Join together the two

screws, seven toothed washers and five nuts. 22 Slide the fuel pump control rod into its seating, assemble the insulator between oil wetted graphite gaskets and fit the pump to the crankcase using nuts and toothed washers. 23 Fit the air conveyor cover complete with the accelera- tor control relay lever and rod. Secure using eight mounting screws, eight toothed washers, eight plain washers and eight nuts. Fit the fuel line retaining clip which is secured by one of the air conveyor upper screws. Install the generator and fan drive pulley having first placed four adjusting rings between the pulley halves and the thrust ring on the outside. Secure the pulley to generator shaft using three screws and three toothed washers. Fit the generator fan drive belt. 24 Refit the carburetter having first positioned the bakelite heat shield between the two oil moistened graphite gaskets. Secure the carburetter using two copper washers and two self-locking nuts. Fit the exhaust silencer and secure to the exhaust manifolds with nuts and spring washers. Place the two graphite gaskets between the manifold joints. Fit both exhaust silencer upper mounting brackets and secure them on the top side to the brackets already in place with nuts and toothed washers on the bottom side with screws and toothed washers. 25 Carefully position the distributor at a 10 deg advance setting and secure with a nut, plain washer and spring washer. Fit the fuel pump to carburetter line complete with mounting bracket rubber lining and secure the line with two clamps. If difficulty is experienced in positioning the fuel line into the pump or carburetter funnels it is suggested that the line ends should be heated in hot water and thoroughly dried before installing. 26 Install the air cleaner elbow and rubber hose assembly on the top of the carburetter using a graphite gasket in between and secure with nuts, plain washers and spring washers. Carefully position the air cleaner, line and hose assembly and connect it to the elbow. Secure the cleaner to air conveyor cover using screws and toothed washers. 27 Fit the spark plug cables complete with the rubber grommet for cable mounting bracket on engine cowling and connect the cables to the distributor and spark plugs. Fit the oil pressure gauge sender unit together with its sealing washer. 28 Install the cylinder head cover and oil breather pipe assembly with a cork gasket inserted between. Secure with self-locking nuts and fibre washers. Connect the accelerator control relay lever rod to the carburetter and secure with the clip. 29 Fill the oil pan with the correct grade and quantity of oil, insert the dipstick and the engine is ready for refitting. 1:18 Engine assembly (station wagon) Reassembly of this engine is straightforward as it is the reverse procedure to dismantling. It is recommended that Sections 1 :5 and 1 :17 are studied as the assembly technique is similar for both the horizontal and vertical F500 31 cylinder engines. The following points should however be noted: 1 Refer to FIG 1 :45 for the correct positioning of the connecting rod-piston assembly on the 120.000 engine. 2 The sequence of tightening the cylinder head nuts is different, the new order being given in FIG 1 :46. Key to Fig 1 :47 1 Suspension arm 2 Screw, rubber pad to bracket 3 Bracket-to-engine nut 4 Nut, arm to bracket 5 Arm bracket 6 Spring 7 Arm pin-to-support nut 8 Screws, pin to support 9 Pin arm to support FIG 1 :47 Power plant rear suspension FIG 1:46 Cylinder head stud nut tightening sequence. 500 D. F and L Sedan and Station Wagon

Power plant front support cross-section FIG 1 :49 Checking the generator and blower drive belt tension 1 :19 Power plant mountings The combined power and transmission unit is elastic- ally mounted on two supports. The front of the unit rests on a crossmember which is secured under the car floor through two rubber block mountings that are bolted to the gearbox casing as shown in FIG 1 :48. The position of the rubber blocks on the crossmember is adjustable so that the assembly can be correctly aligned. With the rear of the unit the engine crankcase is sprung to the body rear crossmember through an articulated swinging arm that compresses a coil spring as shown in FIGS 1 :47 and 1 :49. A rubber bump pad is mounted inside the spring to give a progressive action. Whenever the power and transmission unit is being serviced the condition of the mountings should be checked and any worn or damaged parts renewed. 1 :20 Adjustment of generator and fan drive belt The centrifugal oil filter cover/pulley on the crankshaft transmits the drive through a V-belt to the generator and centrifugal fan pulley. 32 (b) Engine stalls 1 Check 1, 2, 3, 4, 10, 11, 12, 13, 14 and 15 in (a) 2 Sparking plugs defective or gaps incorrect 3 Retarded ignition 1 Defective coil 2 Faulty distributor capacitor (condenser) 3 Dirty, pitted or incorrectly set contact breaker points 4 Ignition wires loose or insulation faulty 5 Water on sparking plug leads 6 Corrosion of battery terminals or battery discharged 7 Faulty or jammed starter 8 Sparking plug leads wrongly connected 9 Vapour lock in fuel pipes 10 Defective fuel pump 11 Overchoking 12 Underchoking 13 Blocked petrol filter or carburetter jets 14 Leaking valves 15 Sticking valves 16 Valve timing incorrect 17 Ignition timing incorrect (a) Engine will not start 1 :22 Fault diagnosis Since its introduction the Fiat new 500 model has been continually developed. The main modifications that have been made are as follows: 1 Heating system safety device 2 Recirculation device for the blow-by gases 3 Cylinder head modified to incorporate item 1 4 Double valve springs fitted 5 Cylinder barrels modified to incorporate item 1 6 Flywheel modified to incorporate new type diaphragm spring clutch mounting 7 Larger air cleaner container. Details of these modifications are to be found in the relevant sections if they necessitate a change in service overhaul procedure. Other information is to be found in Technical Data. 1 :21 Modifications When the V-belt has been correctly adjusted the belt should sag 13/32 inch under a hand pressure of about 22 lb as shown in FIG 1 :49. Should the belt be too slack the generator and centrifugal fan will not operate at the correct speed causing overheating and a discharged battery. Also the belt will slip causing rapid wear of the belt. Conversely if the belt is too tight excessive loading will be placed on the generator bearings causing excessive bearing wear and noisy operation. To adjust the belt tension proceed as follows: 1 Remove the three nuts 'B' (see FIG 1 :49) on the generator pulley and this will split the pulley into two parts between which are spacer rings. 2 The tension of the belt is increased or decreased by either reducing or increasing the number of spacers. 3 Place the spacer rings removed from between the pulley halves on the pulley outer face so that the rings may be re-inserted when fitting a new belt. 4 Tighten the three nuts to a torque wrench setting of 14.5 lb ft. Key to Fig 1 :49 A Normal give-in: about 13/32 inch under a 22 Ib pressure B Nuts securing the pulley halves with spacer rings

5 Water in fuel system 6 Petrol tank vent blocked 7 Incorrect valve clearance (c) Engine idles badly 1 Check 1 and 6 in (b) 2 Air leak at manifold joints 3 Slow-running jet blocked or out of adjustment 4 Air leak in carburetter 5 Over-rich mixture 6 Worn piston rings 7 Worn valve stems or guides 8 Weak exhaust valve springs (d) Engine misfires 1 Check 1, 2, 3, 4, 5, 8, 10, 13, 14, 1 5, 16, 17 in (a); 2, 3, 4 and 7 in (b) 2 Weak or broken valve springs (e) Engine overheats 1 Generator and fan drive belt too loose 2 Shutter or thermostat seized in closed position (f) Compression low 1 Check 14 and 15 in (a), 6 and 7 in (c) and 2 in (d) 2 Worn piston ring grooves 3 Scored or worn cylinder bores (g) Engine lacks power 1 Check 3, 10, 11, 13, 14, 15, 16 and 17 in (a), 2, 3, 4 and 7 in (b) 6 and 7 in (c) and 2 in (d). Also check (e) and (f) 2 Leaking joint washers 3 Fouled sparking plugs 4 Automatic centrifugal advance not operating (h) Burnt valves or seats 1 Check 14 and 15 in (a), 7 in (b) and 2 in (d). Also check (e) 2 Excessive carbon around valve seat and head (j) Sticking valves 1 Check 2 in (d) 2 Bent valve stem 3 Scored valve stem or guide 4 Incorrect valve clearance (k) Excessive cylinder wear 1 Check 11 in (a) and see Chapter 4 2 Lack of oil 3 Dirty oil 4 Piston rings gummed up or broken 5 Badly fitting piston rings 6 Connecting rods bent (l) Excessive oil consumption 1 Check 6 and 7 in (c) and check (k) 2 Ring gaps too wide 3 Oil return holes in piston choked with carbon 4 Scored cylinders 5 Oil level too high 6 External oil leaks 7 Ineffective valve stem oil seals (m) Crankshaft and connecting rod bearing failure 1 Check 2 in (k) 2 Restricted oilways 3 Worn journals or crank pins 4 Loose bearing caps 5 Extremely low oil pressure 6 Bent connecting rod (n) High fuel consumption (see Chapter 2) (o) Engine vibration 1 Loose generator bolts 2 Blower blade assembly out-of-balance 3 Incorrect clearance for rear engine mounting rubber F500 33

2:1 Description 2:2 Fuel pump operating principles 2:3 Routine maintenance 2:4 Pump removal, dismantling and examination 2:5 Reassembly, installation and adjustment 2:6 Carburetter operation and adjustment, Weber 26.1MB 2:7 Modifications 2:8 Carburetter operation and adjustment, Weber 26.OC 2 :9 Air cleaner 2:10 Blow-by gases recirculation device 2:11 Fuel tank 2:12 Fault diagnosis 2:1 Description All the new 500 models use a mechanical diaphragm fuel feed pump as shown in FIG 2:1. Four types of carburetter are fitted depending on the model to which the engine is installed. Each carburetter operation and adjustment is fully described, together with details of the recirculation device for blow-by gases and oil vapours. 2:2 Fuel pump operating principles Refer to FIG 2 :2. An eccentric on the rotating camshaft actuates the operating rocker 21 via a pushrod 25 which depresses the diaphragm 14 and so creates a depression in the pumping chamber located in upper body 5. Under atmospheric pressure, petrol passes through the pipeline connection and inlet valve into the pumping chamber. The return spring 15 then raises the diaphragm, expelling the petrol through the outlet valve and pipeline to the carburetter float chamber. When the float chamber is full, the pressure in the pipe- line and pumping chamber holds the diaphragm depressed against the tension of the return spring. 2:3 Routine maintenance A poor delivery of fuel to the carburetter may be due to a fault in the fuel pump or related lines. Periodically the pump body screws 19 (see FIG 2:2) and upper cover screw 1 should be checked for tightness. The fuel pump lines should be disconnected and checked for freedom of restriction, chafing and loose connections. The fuel pump filter should be removed and cleaned periodically. 2:4 Pump removal, dismantling and examination The pump is located on the carburetter side of the engine crankcase (sedan) or under the generator at the front of the crankcase (station wagon). Removal: 1 Disconnect the fuel pipe from the tank to stop petrol syphoning out of the tank and then release the fuel inlet and outlet pipes from the pump body. 2 Remove the two nuts and washers holding pump to crankcase. 3 Carefully lift away the pump, gaskets and insulating pad from the crankcase (see FIG 2:3). F500 35

FIG 2:2 Fuel pump components KeytoFig2:2 1 Cover screw 2 Screw gasket 3 Cover gasket 4 Cover 5 Upper body 6 Spring for inlet valve 7 Inlet valve 8 Outlet valve 9 Spring for outlet valve 10 Plate gasket 11 Plate screws 12 Valve retaining plate 13 Filter gauze 14 Diaphragm, complete with tie rod 15 Return spring 16 Spring thrust cup 17 Felt 18 Washer for felt 1 9 Connection screws 20 Lower body 21 Rocker 22, 24 Gaskets 23 Insulating pad 25 Pump control pushrod 36 FIG 2:3 Fuel pump and control pushrod FUEL PUMP CONTROL PUSHROD INSULATING PAD FUEL PUMP All 500 Sedans are equipped with Weber type 26. IMB carburetters with detail differences only between the models. The carburetter is of a downdraft single choke 2:6 Carburetter operation and adjustment, Weber 26.IMB Carefully slide the pump control pushrod into the crankcase, assemble the two gaskets with the insulating pad in between and slide over the pump retaining studs. Ease the pump towards the crankcase ensuring the push- rod locates correctly in the rocker end. Finally tighten the two retaining nuts and spring washers. Installation: Ensure that all parts are clean and dry. Assembling is the reverse procedure of dismantling. Lubricate the rocker lever and pin before placing them in the lower body. 2:5 Reassembly, installation and adjustment 1 Refer to FIG 2:2 and remove the cover mounting screw 1 and washer 2. Lift off cover 4 and filter 13. Mark the relative position of the two halves of the pump body. Remove the pump bodies interlocking screws 19 and separate the upper half from the lower half of the body. 2 Push down the centre of the diaphragm assembly 14 and rotate through 90 deg. to release diaphragm from the rocker 21. Lift out diaphragm and spring 15. 3 Release the two valve assemblies in the upper body by removing the valve retaining plate locking screws 11, and lifting out the plate 12, gasket 10, valve springs 6 and 9, and valves 7 and 8. 4 Using a pin punch remove the rocker pivot pin together with the two washers and carefully lift away rocker and reaction spring. 5 Thoroughly wash all components in petrol and blow dry with compressed air or a foot pump. Inspect the valves 7 and 8 for evidence of damage and valve springs 6 and 9 for weakness or cracks. Check to see that the diaphragm reaction spring and rocker are not distorted or unserviceable. Generally inspect all parts for cracks, distortion and the diaphragm for stiffness and also the rocker and pin for wear. Dismantling:

KeytoFig2:5 A Device fully inserted B Device partially inserted C Device disinserted 2 Air inlet 16 Bowl 19 Throttle 21 Primary venturi 24 Secondary venturi 26 Mixture duct 27 Mixture leaning air orifice 28 Transition duct 29 Transition mixture orifice 30 Starting mixture orifice 31 Transition orifice 32 Starting mixture orifice 33 Starting valve 34 Mixture duct 35 Starting device air orifices 36 Rocker 37 Lever return spring 38 Starting device control lever 39 Control wire screw 40 Cover with support for starting device control bowden 41 Starting valve spring 42 Spring casing. 43 Starting jet emulsion air orifice 44 Air emulsion reserve well orifice 45 Starting reserve well 46 Starting jet F500 37 FIG 2:4 Diagrammatic section of Weber 26.IMB carburetter K e y t o F i g 2 : 4 1 Air corrector jet 2 Air inlet 3 Idle speed mixture duct 4 Idle speed jet holder 5 Idle speed air orifice 6 Filter cover 7 Filter 8 Fuel inlet connection 9 Needle valve seat 10 Needle 11 Float pivot 12 Float 13 Idle speed jet 14 Main jet holder 15 Main jet 16 Bowl 17 Idle speed mixture adjustment screw 18 Idle speed mixture orifice 19 Throttle 20 Transition hole 21 Primary venturi (not interchangeable) 22 Emulsion orifices 23 Emulsion well 24 Secondary venturi (not interchangeable) 25 Main nozzle design with a 1.0236 inch diameter throat measured at the height of the throttle shaft. The amount of charge passing to the manifold is controlled by a throttle butterfly valve from an accelerator pedal operating a lever secured to the throttle valve shaft via a cable. The carburetter is fitted with a progressive action starting device which enables the driver to suit the mixture richness to the most arduous of starting conditions, and will enable the engine to run evenly until it reaches its normal operating temperature. A dampened needle valve ensures a smooth running engine as it is not affected by engine vibrations and there- fore giving a constant fuel level in the carburetter bowl. A secondary venturi is incorporated in the single casting of the carburetter body and this has a diameter of 0.8268 inch. Carburetter operation: Filtered air flows through the venturi 24 (see FIG 2 :4) where it mixes with fuel flowing from the nozzle 25 and the charge is then conveyed to the cylinders through the primary venturi 21 and throat, where the throttle butterfly 19 controls the amount of charge. Petrol flows from the main fuel line to the bowl 16 through a gauze filter 7 and needle valve 10, where the float 12 pivoting at point 11, controls the opening of the needle 10 so maintaining a constant fuel level. From the bowl 16 fuel reaches the emulsion well 23 via the metered main jet 15 where, after having been mixed with the air coming from the metered air corrector screw 1, through the emulsion orifices 22 and spray nozzle 25, it finally reaches the Venturis where it mixes with the air stream

(choke) end Key to Fig 2:6 1 Choke device cover 2 Bowden mounting screw 3 Nut and screw, choke bowden wire 4 Choke control lever A Position of lever 4 for 'fully inserted' choke B 'Partially inserted' choke C 'Disinserted' choke caused by the engine suction and the charge is then drawn into the cylinders. The secondary venturi 24 is to increase the vacuum around the nozzle 25 and to carry the charge to the centre of the primary venturi 21. When the engine is idling, fuel is carried from the well 23 via an appropriate passage to the idle speed jet 13 where it is mixed with the air coming from the air inlet 5. Through duct 3 and idle speed orifice 18 (adjustable by means of a taper point screw 17), the fuel reaches the carburetter throat, past throttle butterfly 19 where it is further mixed with the air stream drawn in by the engine vacuum through the gap around the throttle in the idling speed position. From the duct 3 the mixture can also reach the car- buretter throttle chamber through a transition hole 20 which is located in exact relation to the throttle butterfly. The purpose of this progression hole is to permit a smooth acceleration of the engine from the idling speed, this being proportional to the increase in the throttle opening. Starting device: This enables the engine to be started when it is cold under the most arduous of weather conditions. It is con- trolled by means of a lever placed behind the gearshift lever and must be progressively adjusted to its normal rest position as the engine reaches the normal operating tem- perature. The starting device comprises a valve 33 (see FIG 2:5) actuated by the lug of the rocker 36 which is connected to the control lever 38 by a suitable shaft. By 38 pulling the device control fully across through lever 38 and rocker 36, the valve 33 is lifted from its seating and brought into the 'fully open' position. Refer to diagram 'A' (FIG 2:5). Under these conditions the valve 33 closes the air hole 27 and the mixture hole 29 and uncovers mixture orifices 30 and 32 which also communicate with the starting jet 46 through a duct 26 and air holes 35. With the valve 33 partially open the hole 29 may com- municate with the carburetter throat through the valve central slot, duct 28 and the hole 31 drilled in the venturi 21 corresponding with the venturi restriction. When the throttle is set at the idling speed position, the engine vacuum caused by the operation of the starter enables the fuel contained in the recess of jet 46, in the jet and in the reserve well 45 to be mixed with the air coming from holes 43 and 44. The mixture arrives through the duct 26 and holes 30 and 32, at the same time as air passing from the holes 35, past the throttle through duct 34 so permitting easy starting of the engine. After the engine has fired initially, the device will deliver a charge with a rich petrol/air ratio so as to permit regular running of the engine whilst it is cold. As soon as the engine has warmed up to normal operating temperature this charge would obviously be too rich and therefore it is necessary to gradually ease off the operation of the starting device as the engine reaches its normal operating tempera- ture. During this adjustment the valve 43 slowly uncovers the hole 27 which will permit a greater amount of air to enter through the spring guide hole 42 so weakening the mixture at the same time as closing the progression holes 30 and 32 and air holes 35 the amount of mixture is also reduced. See diagram 'B' (FIG 2:5). The hole 29, the duct 28 and the hole 31, which are drilled in the venturi 21 permit a regular progression of acceleration whilst the engine is cold as well as when it is at normal operating temperature. By opening the throttle butterfly 19 to increase the speed of the engine the vacuum acting on the duct 34 is decreased. This causes a drop in the amount of fuel delivered through duct 34 with consequent irregular running of the engine but, through hole 31, duct 28 and hole 29 some charge is sucked in by the vacuum formed in the restriction of the venturi, caused by the opening of the throttle and this automatically com- pensates for the reduction in the delivery through the duct 34. When the starting device is not in operation, valve 33 covers the hole 29 and so preventing the passing of fresh charge. Diagram 'C (FIG 2:5). Engine starting: So that full advantage may be taken of the progressive action starting device the engine should be started as follows: 1 Cold starts: The starting device should be moved across the position 'A', (FIG 2:6). Once the engine has fired push the control in partially. 2 Warm starts: Only partially move the starting device as shown in position 'B' (FIG 2:6).

As the engine begins to warm up to its normal operating temperature, gradually push home the starting device lever so as only to supply the engine with the richened charge enabling the cold engine operation to be smooth and regular. Position 'B' (FIG 2:6). 4 Normal car driving: Once the engine has reached its normal operating temperature the starting device should be completely brought out of operation by bringing the control lever to the position 'C (FIG 2:6). Idle speed adjustment: The idling speed of the engine is adjusted by means of a throttle setscrew and the mixture setscrew, the position of which are shown in FIG 2:7. The throttle screw allows for the adjustment of the throttle butterfly opening, the coni- cal mixture setscrew meters the amount of charge issuing from the idling speed passage which causes the mixture to blend with the air flowing past the throttle that leaves a gap between its edges and the throat walls. This ensures a correct petrol/air mixture ratio best suited to the engine requirements giving smooth operation. The engine idling speed must always be adjusted when the engine is at its normal operating temperature and then setting the throttle butterfly position to its minimum open- ing position by adjusting the throttle setscrew so giving a steady engine speed. Turn the mixture screw in or out so as to set the mixture richness to the most suitable ratio for the selected throttle opening. This will accomplish a fast but steady idling. Reduce the minimum throttle opening slightly by adjusting the throttle setscrew until the best idling speed is obtained. Adjustment of fuel level in float chamber: The needle valve, seating and float are easily accessible for inspection by removing the carburetter top cover. Before checking the petrol level in the float chamber, ensure that the needle valve seat is screwed well home and that the gasket is in place. Also check that the calibrated orifice in the valve seat is unobstructed and not worn and finally check that the needle slides freely in its guide. Should the valve and seating be leaking, then the valve assembly must be renewed. Check that the float is not distorted or punc- tured and that it moves on its pivot without resistance or excessive play. Again renew the float assembly if there is any doubt. To check the level proceed as follows: 1 Check that the needle valve 3 (see FIG 2 : 8) is screwed tight on its seat. 2 Keep the carburetter cover 1 upright or else the weight of the float 9 will lower the ball 8 fitted on the needle 4. Check that with the cover held in the vertical position and the float arm 6 in slight contact with the ball 8 of the needle 4, the float is 5/16 inch away from the cover with its gasket 2 fitted flat against the cover face. 3 Check that the float travel is 5/16 inch and if necessary bend the lug 5 to give the required settings. 4 If the float 9 is not correctly positioned, bend the float arms 7 until the correct adjustment is obtained. Ensure that the arm 6 is perpendicular to the needle axis and F500 39 does not show any rough spots or indentations which might impair free movement of the needle. Check that the float 9 freely moves about its pivot pin. Every time a new float or needle valve assembly is fitted the above detailed adjustment operations must be com- pleted to ensure correct fuel levels. FIG 2:8 Float adjustment data Key to Fig 2: 8 1 Carburetter cover 2 Cover gasket 3 Needle valve seat 4 Needle 5 Lug 6, 7 Arms 8 Needle ball 9 Float 7 .2756 inch 15 .5906 inch FIG 2:7 Weber 26.IMB carburetter in place on engine. Idle speed is adjusted by working respectively on throttle setting screw and mixture metering screw THROTTLE SETTING SCREW MIXTURE METERING SCREW

Key toFig 2:9 1 Float 2 Carburetter cover 3 Float pivot 4 Needle valve gasket 5,6 Needle valve seat and needle valve 7 Cover gasket 8 Filter strainer 9 Gasket 10 Filter inspection plug Carburetter cleaning: To thoroughly clean the carburetter proceed as follows: 1 Passages. All fuel passages have a diameter that is specially calibrated to ensure best operating conditions. It is therefore essential that any dirt or scale that has been deposited by petrol must be removed. Thoroughly clean with petrol and blow dry using a compressed air jet directed through all the passages in the castings. It is essential that no drills or other metal objects be passed through the jets or the passages otherwise these could alter the finely calibrated diameters. 2 Calibrated parts. Idling and main jet holders, and the relevant bayonet coupled jets are easily removed by using a suitably sized wrench or screwdriver. To clean the different calibrated parts, thoroughly wash in petrol and blow dry using a compressed air jet. Do not use any fine drills or metallic points as these may alter the fine calibration of the orifices. Should it be necessary to dis- mantle the carburetter adjustment components for inspection always ensure that after reassembly of the parts that they are seated correctly to avoid possible operating troubles in the future. 3 Filter. To clean the filter unscrew and remove its plug 10 (see FIG 2 :9) located on the top of the carburetter cover and then gently ease out the filter. Wash the filter carefully in petrol, also ensure that the filter seat is clean and then blow dry using a compressed air jet. 2:7 Modifications The Weber 26.IM B carburetter has undergone a number of minor changes during the development of the Fiat 500 models, but no changes in servicing procedure are made necessary. Jet sizes and other calibrations are detailed in Technical Data. From 1970, the mounting flange of the carburetter is slightly modified to incorporate a different mixture adjustment screw, as shown in FIG 2:11. 40 Throttle valve components: The throttle valve shaft should rotate freely in its guides and this should be checked when the engine is at its normal operating temperature. Any excessive clearance caused by wear or the throttle valve butterfly distorted are liable to cause irregular engine operation which will be more pronounced at idling speed. Should the above con- ditions be evident then the throttle valve butterfly and the shaft assembly together with its sealing rings must be renewed. FIG 2:10 Jets, jet holders and choke valve Key to Fig 2:10 1 Choke valve 2 Spring 3 Spring retainer and guide 4 Lock ring 5 Air bleed jet 6 Emulsion well 7 Choke jet 8 Idling jet holder and jet 9 Main jet holder and jet 10 Main jet holder gasket

26.IMB.4 and later carburetters. It differs from earlier units in detail, principally in having fewer starting mixture orifices 30 and 32 into the mixture duct 26. 2:8 Carburetter operation and adjustment, Weber 26. OC The new 500 station wagon is fitted with the Weber 26.OC carburetter which is of a horizontal draft design to suit the engine which is fitted in the horizontal position. The carburetter is fitted with a progressive action starting device which enables the driver to adjust the mixture rich- ness to the most arduous of starting conditions, and will enable the engine to run eyenly until it reaches normal operating temperature. A dampened needle valve ensures a smooth running engine as it is not affected by engine vibrations and there- fore giving a constant fuel level in the carburetter bowls. A secondary venturi is incorporated in the single casting of the carburetter body. Carburetter operation, starting device: The petrol from bowl 23 (see FIG 2:13) reaches the starting jet 37 through the duct 35. By operating the choke lever 31 to the end of its stroke, the valve 30 is lifted from its seat and brought to the 'fully open' position as shown in diagram 'A' (FIG 2:13). Under these conditions the valve 30 uncovers both the starting mixture ducts 28 and 29. With the throttle set in the idling speed position the engine vacuum created by the operation of the starter motor causes the fuel contained in the recess of jet 37 in the jet and the reserve well 36 to be mixed with the air coming from the air jet 38. The mixture arrives through the ducts 28 and 29 at the same time as air from holes 34, past the throttle so per- mitting easy starting of the engine. A B C FIG 2:12 Section of later starting device Key to Fig 2:12 A Cold starting position B Warming up position C Normal running position 2 Air inlet 21 Primary venturi 24 Secondary venturi 26 Mixture duct 27 Air bleed 30,32 Starting mixture orifices 33 Valve 34 Mixture duct 35 Air orifices 38 Rocker 39 Lever return spring 40 Control lever 41 Control wire screw 42 Cover and cable support 43 Valve spring 44 Spring guide and retainer 45 Starting jet emulsion air duct 46 Emulsion air reserve well duct 47 Reserve well 48 Starting jet F500 41 Once the engine has initially fired the starting device will deliver a mixture whose petrol/air ratio is such that the engine will run regularly even though it is cold. As soon as the engine warms up this rich charge would be excessive and therefore it becomes necessary to gradually ease back the operation of the starting device. As this is occurring, the valve 30 gradually covers up the mixture duct orifice 28 so as to weaken the mixture while by closing the duct 29 gradually. It also reduces the amount of mixture delivered by the carburetter as shown in diagram 'B' (FIG 2:13). FIG 2:11 Mounting flange modification: A earlier, B later (dimensions in mm)

1 2 .3 4 5 27 26. 25, 24. 23. 22 16 17 8 21 20 9 _6 .4 7 .8 10 19 18 17 16 15 9 5 10 11 12 13 14. FIG 2 :14 Diagrammatic section views of 26.OC Weber carburetter Key to Fig 2:14 1 Fuel inlet connection 2 Filter gauze 3 Filter inspection plug 4 Air corrector jet 5 Air intake 6 Idle speed jet holder 7 Idle airduct 8 Emulsion tube 9 Secondary venturi 10 Idle mixture duct 11 Primary venturi 12 Progression hole 13 Idle orifice to duct 14 Idle mixture adjustment screw 15 Throttle 16 Bowl-to-well duct 17 Emulsion tube housing well 18 Well-to-idle jet duct 19 Idle speed jet 20 Nozzle 21 Emulsion orifices 22 Main jet 23 Bowl 24 Float 25 Float pivot 26 Valve needle 27 Needle valve When the starting device is not in operation valve 30 covers the hole 29 so preventing the passage of mixture as shown in diagram 'C (FIG 2:13). Engine starting: So that full advantage may be taken of the progressive action starting device the engine should be started as follows: 1 Cold starts. The starting device should be moved across to position 'A' as shown in FIG 2:13. Once the engine has fired push the control in partially. 42 2 Warm starts. Only partially move the starting device to position 'B' as shown in FIG 2:13. 3 Engine warm-up. As the engine begins to warm up to its normal operating temperature. Gradually push home the starting device lever so as only to supply the engine with the richened charge enabling the cold engine. operation to be smooth and regular. Position 'B'shown in FIG 2:13. 4 Normal car driving. Once the engine has reached its normal operating temperature the starting device should be completely brought out of operation by bringing the control lever to the position C shown in FIG 2:13. Key to Fig 2:13 23 Bowl 28 Starting mixture duct 29 Starting mixture duct 30 Starting valve 34 Emulsion air orifices 38 Starting air corrector screw C Choke disengaged B Choke partially inserted 37 Starting jet 33 Bowden fixing screw A Choke fully inserted 36 Starting reserve well 32 Starting device control wire 31 Starting device control lever 35 Bowl-to-starting jet duct 39 Reserve well emulsion air slot

buretter type 26.OC 7.5 = .29 inch 14.5 = .57 inch Key to Fig 2:15 1 Carburetter cover 2 Cover gasket 3 Needle valve 4 Valve needle 5 Lug 6, 7 Arms 8 Needle ball 9 Float Idle speed adjustment: The idling speed is adjusted by movement of the throttle setscrew and the mixture setscrew. The throttle screw allows for the adjustment of the throttle opening whereas the conical mixture setscrew has the purpose of metering the amount of charge issuing from the idling speed pas- sage, which will then mix with the air flowing past the throttle which when correctly set for normal idling speed should leave a gap between its edges and the throat walls. This ensures a correct petrol/air ratio best suited to the engine requirements and smooth operation. The idling speed should always be adjusted with the engine running and at its normal operating temperature by first setting the throttle to its minimum opening by turning the throttle setscrew so enabling an accurate adjustment to be made. Then slowly turn the mixture set- screw either in or out so as to adjust the mixture petrol/air ratio to the most suitable for the throttle opening, this will accomplish a fast and steady idling speed which should be then reduced by closing the throttle opening slightly by easing back the throttle setscrew. This adjustment should continue until the best idling speed is obtained. Adjustment of fuel level in float chamber: To check and adjust the level of fuel in the carburetter float chamber proceed as follows: 1 Check that the needle valve 3 (see FIG 2:15) is screwed tight on its seat. 2 Keep the carburetter cover 1 upright or else the weight of the float 9 will lower the ball 8 fitted on the needle 4. F500 43 Key to Fig 2:17 1 Filter housing 2 Spring hooks 3 Filter element 4 Cover 5 Air suction pipe, hoses and clamps 6 Re-circulation pipe for blow-by gases and oil vapours FIG 2:17 Removing the air cleaner, 500F, L 2 1 3 4. 6 5 FIG 2:16 Taking out the filter element, 500, 500D AIR CLEANER ELBOW HOSE AIR CLEANER BODY •FILTER ELEMENT Check that with the cover held in the vertical position and the float arm 6 in slight contact with the ball 8 of the needle 4, the float is .2953 inch away from the cover with its gasket 2 fitted flat against the cover face. 3 Check that the float level is .5709 inch from the cover face and if necessary bend the lug 5 to give the required setting. 4 If the float 9 is not correctly positioned bend the float arm 7 until the correct adjustment is obtained. Ensure that the arm 6 is perpendicular to the needle axis and does not show any rough spots or indentations which might impair free movement of the needle. Check that the float 9 moves about its pivot pin. Every time a new float or needle valve is fitted the above detailed adjustment operations must be completed to ensure correct fuel levels.

Key to Fig 2:18 1 Head cover 2 Blow-by gases and oil vapours breather valve 3 Oil filler cap 4 Strainer 9 Air suction pipe, air cleaner to carburetter 8 Flame trap 13 Exhaust duct 12 Crankcase 7 Carburetter 6 Air cleaner 11 Filter gauze 10 Movable partition 5 Pipe Engine 110 F. 000 Engine 120.000 designed to dampen the air intake noise and the carburet- ter venturi hiss and is so located in the blower conveyor system so that only clean dry air is drawn into the induc- tion system. To ensure complete protection of the engine it is recommended that the air filter element be replaced every 6000 miles or even earlier if the vehicle is operating in dusty conditions. It should be noted that an oversize air cleaner may be obtained if the vehicle is to be operated in very dusty areas. Air cleaner—engine 110 F.000: To remove the air cleaner element, disengage both the spring hooks 2 as shown in FIG 2:17 and lift away the cover 4 by turning it inwards together with the hose 5. 2:9 Air cleaner (sedan) The pleated paper air cleaner element is contained in a casing housed in a recess of one of the silencing chambers provided in the blower conveyor as shown in FIG 2:16. The air cleaner is connected to the carburetter by means of a specially shaped hose. The silencing chamber is 44 For full instruction refer to Section 2 :6. Carburetter cleaning: See Section 2 :6 for full check details. Throttle valve components: Engine 110 F. 000

A pleated paper air cleaner element is housed in a special air intake chamber connected to the front of the engine air cooling cowling (see FIG 4:2). This chamber will be seen located towards the rear of the power unit compartment. Remove the retaining wing nut, lift off the lid and the element can be withdrawn by lifting upwards. 2:10 Blow-by-gases recirculation device Engine 110 F.000 All the oil vapours and blow-by-gases that are formed in the engine crankcase are drawn to the cylinder head cover recess 1 (see FIG 2:18). From here they travel into the pipe 5 via a breather valve 2 which is firmly attached to the oil filler cap 3 and the strainer 4 located in the filler neck. The oil vapours and gases are then drawn back into the duct 9 from the pipe 5 which connects the air cleaner 6 to the carburetter 7. This ensures a complete closed cir- cuit circulation. Engine 120.000: From engine No. 288156 the oil vapours and blow-by- gases instead of being exhausted to the atmosphere are conveyed to the air cleaner and from here they are drawn back into the combustion chambers. To ensure that an excessive of oil vapour does not pass along the piping with the blow-by-gases a diaphragm is fitted in the duct in front of the breather valve 2 (see FIG 2 :18), the dia- phragm comprising a filter gauze 11 and moveable parti- tion 10. It should be noted that the oil vapour strainer 4 (see FIG 2:18) and the flame trap 8 can easily be removed from their seating for cleaning or renewal. 2:11 Fuel tank The fuel tank is located in the front compartment as shown in FIG 2:19, it comprises a filler union fitted with a cap, a fuel reserve supply indicator sender unit and a con- nection incorporating a filter for the main fuel supply pipes. To remove the tank proceed as follows: 1 Remove the contents of the front compartment includ- ing the spare wheel and tool bag. 2 Disconnect the main fuel line at the sender unit and also disconnect the cable to the fuel reserve supply indicator. 3 Remove the four screws together with the clips that fix the tank to the body and carefully lift away the fuel tank. 4 Carefully drain the contents of the tank into a clean dry container of a suitable capacity. Fuel tank—sedan (110 F.) and station wagon (120): The fuel tank is arranged in the front compartment as shown in FIG 2 :20. To remove the fuel tank proceed as follows: 1 Remove both screws which secure the front ends of the clamping bands to the dash panel. The screws are shown by arrows in FIG 2 :20. Petrol tank cleaning: The tank must be thoroughly checked for leaks espe- cially at the joint seams. Should a leak be found it is F500 45 advisable for a garage to attend to this as it is very dange- rous to apply heat to a petrol tank without first taking strict precautions and a garage will be in a better position to do this. To clean the tank interior, remove the drain plug and spray in a jet of air or petrol so that all sediment and dirt deposits can be loosened. Then vigorously shake the tank. Flush the tank with petrol and blow the tank dry. Repeat this procedure until the tank is clean. Refit the drain plug. Whilst the petrol tank is away from the car it is advisable to disconnect the fuel feed pipes at the pump and the carburetter and ensure that these are clear by using an air jet to one end of the pipe. Key to Fig 2 :20 Note Arrows point to fuel tank clamping band screws vent valve indicator tank unit 1 Fuel tank 2 Filler cap with 3 Fuel suction pipe and reserve supply 4 Tank clamping bands FIG 2:20 Location of the fuel tank in front compart- ment, 500F, L FIG 2:19 Fuel tank in front compartment. The fuel reserve supply indicator (red light) glows when fuel amount in tank is less than .8 to 1.1 Imp galls, or 5 litre FUEL TANK FUEL LINE TO PUMP FUEL GAUGE CABLE

(a) Leakage or insufficient fuel delivered 1 Air vent in tank restricted 2 Petrol pipes blocked 3 Air leaks at pipe connections 4 Pump or carburetter filters blocked 5 Pump gaskets faulty 6 Pump diaphragm defective 7 Pump valves sticking or seating badly 8 Fuel vapourizing in pipelines due to heat (b) Excessive fuel consumption 1 Carburetter needs adjusting 2 Fuel leakage 3 Sticking controls or choke device 4 Dirty air cleaner 5 Excessive engine temperature 6 Brakes binding 7 Tyres under-inflated 8 Idling speed too high 9 Car overloaded (c) Idling speed too high 1 Rich fuel mixture 2 Carburetter controls sticking 3 Slow-running screws incorrectly adjusted 4 Worn carburetter butterfly valve (d) Noisy fuel pump 1 Loose mountings 2 Air leaks on suction side and at diaphragm 3 Obstruction in fuel pipe 4 Clogged pump filter (e) No fuel delivery 1 Float needle stuck 2 Vent in tank blocked 3 Pipeline obstructed 4 Pump diaphragm stiff or damaged 5 Inlet valve in pump stuck open 6 Bad air leak on suction side of pump 46

3 : 3 3 : 4 3 : 5 Description Operation Routine maintenance Ignition faults Removing and dismantling distributor (sedan and sports) CHAPTER 3 THE IGNITION SYSTEM 3 : 6 3 : 7 3 : 8 3 : 9 3 : 1 0 Removing and dismantling (station wagon) Timing the ignition Sparking plugs The distributor drive spindle Fault diagnosis distributor 3 :1 Description The ignition system fitted to all the models covered by this manual consists of an ignition coil, ignition distributor fitted with contact breaker points, a centrifugal automatic advance system, condenser, low- and high-tension wiring, spark plugs and a power supply provided by a generator and battery. The wiring diagram is shown in FIG 3:1 1 The low-tension circuit which is sometimes called the primary circuit includes the power supply, contact breaker points, condenser and ignition coil primary winding. 2 The high-tension circuit which is sometimes called the secondary circuit includes the ignition coil secondary winding, distributor rotor, distributor cap with terminals and the central brush, high-tension cables and the spark plugs. 3:2 Operation The contact breaker unit in the distributor interrupts the primary circuit by the points opening. The sudden stop in the flow of current in the primary winding, does not cause arcing at the contact breaker points because it discharges into the condenser connected in parallel with the contact F500 47 breaker points. With the sudden collapse of the primary circuit, the intensity of the magnetic field drops causing an induced high-tension current in the ignition coil secondary winding. The high EMF is distributed to the sparking plugs by the ignition distributor rotor. The automatic advance mechanism comprises a plate carrying two weights which are symmetrically pivoted on the plate at one end. Also attached to the weights at opposite ends to the pivots is the cam carrier shaft with special tension return springs. Under the action of centri- fugal force as the rotational speed increases, the weights move outwards causing the cam carrier shaft to move angularly compared to the distributor drive shaft thus causing advancement of the ignition timing. The contact breaker assembly comprises the cam on the drive shaft and two contact points, one of which is stationary while the other is under the influence of the cam, the action of which is transmitted by a rubbing block. The cam has two lobes to control the opening and closing of contact points. The stationary contact point is mounted on an adjustable support to enable the contact breaker point gap to be adjusted. The HT current reaches the distributor cap central terminal, from the ignition coil and is distributed to each of the spark plugs at the correct time by the rotor arm.

BATTERY SWITCH BREAKER COIL SPARK PLUG CONDENSER FIG 3:2 Ignition distributor in place on engine with cap lifted off CURRENT CONTACT TO SPARK PLUG BREAKER ARM STATIONARY CONTACT CARRIER ADJUSTING SCREW CONTACT POINTS HIGH TENSION) CARBON CONTACT 3:3 Routine maintenance Refer to FIG 3: 2 and remove the distributor cap and lift off the rotor arm. Lubricate the cam spindle felt pad using Fiat VS oil. There is provision for the oil to make its way downwards. Squirt a few drops of oil into the distributor shaft lubrication fitting, the location being shown in FIG 3:3 Smear a little grease on the cam and a small drop of oil to the contact breaker point pivot. Adjusting the contact breaker points: Refer to FIG 3:2 and slacken the stationary contact carrier adjusting screw. Slowly rotate the engine until one one of the two cams has opened the points to the fullest 48 extent so that the gap is measured at the position of the maximum opening. Reset the gap to a correct clearance of .0185 to .0209 inch and tighten the contact carrier screw. Cleaning the contact points: If the contact points are dirty or pitted they must be cleaned by polishing them with a fine carborundum stone taking very great care to ensure that the contact faces are flat and square. Afterwards wipe away all dust with a cloth moistened in petrol. The contacts may be removed from the distributor body to assist refacing and cleaning refer- ring to Section 3:5. If the moving contact is removed from its pivot, check that its operation is not sluggish. If it is tight, polish the pivot pin with a strip of fine emery cloth, clean off all dust and apply a tiny spot of oil to the top of the pivot pin. If a spring testing gauge is available the contact breaker spring should have a tension of 16.8± 1.8 oz. measured at the points. 3 :4 Ignition faults If the engine runs unevenly set it to idle at a fast speed. Taking care not to touch any metal part of the sparking plug leads, pull up the insulator sleeve and short each plug in turn, using a screwdriver with an insulated handle. Connect the screwdriver blade between the plug top and the cylinder head. Shorting a plug which is firing properly will make the engine uneven running more pronounced. Shorting a plug in a cylinder which is not firing will make no difference. Having located the faulty cylinder, stop the engine and remove the plug lead. Start the engine and hold the lead carefully to avoid shocks so that the metal end is about 3/16 inch away from the cylinder head. A strong regular spark shows that the fault might be with the sparking plug. Remove and clean it according to the instructions in Section 3 :8. Alternatively substitute it with a new plug. If the spark is weak and irregular, check that the lead is not perished or cracked. If it appears to be defective, renew it and try another test. If there is no improvement, remove the distributor cap and wipe the inside clean and dry. Check the carbon brush located as shown in FIG 3 :2. It should protrude from the cap moulding and be free to move against the pressure of the internal spring. Examine the surface inside the cap for signs of 'tracking' which can be seen as a thin black line between the electrodes or to some metal part in contact with the cap. This is caused by sparking, and the only cure is to fit a new cap. Testing the low-tension circuit: Before carrying out electrical tests, confirm that the contact breaker points are clean and correctly set, then proceed as follows: 1 Disconnect the black low-tension cable from the ignition coil and from the side of the distributor. Connect a test lamp between the two terminals. Turn the engine over slowly. If the lamp lights when the contacts close and goes out when they open, the low-tension circuit is in order. If the lamp fails to light the contacts are dirty or there is a break or loose con- nection in the low-tension wiring. 2 If the fault lies in the low-tension circuit, switch on the ignition and turn the crankshaft until the contact breaker points are fully open. Refer to the wiring diagram in Technical Data and check the circuit with

should read approximately 12-volts. 3 Battery to fuse box terminal 30. Connect the volt- meter between the terminal 30 and earth. No reading indicates a faulty cable or loose connection. 4 Fuse box. Connect the voltmeter between the other auxiliary terminal 30 and earth. No reading indicates a broken or loose connection. 5 Fuse box auxiliary terminal 30 to terminal number 30 on ignition switch. Connect the meter between terminal number 30 on the ignition switch and earth. No reading indicates a damaged cable or loose connection. 6 Ignition switch. Connect the meter between termi- nal 15/54 and earth. Switch onto the ignition position, when no reading indicates a fault in the switch. 7 Ignition switch to low-tension cable connection on the coil (blue cable). Connect the meter between ignition coil terminal (blue cable) and earth. No reading indicates a damaged cable or loose con- nection. 8 Ignition coil. Disconnect the black low-tension cable connecting the coil to the distributor side terminal at the coil and connect the meter between this terminal and earth. No reading indicates a fault in the primary winding of the coil and a replacement coil must be fitted. If the reading is correct remake the connections to the coil. 9 Ignition coil to distributor. Disconnect the thin black low-tension cable at the side of the distributor and connect the meter between the end of this cable and earth. No reading indicates a damaged cable or loose connections. 10 Contact breaker and capacitor. Connect the meter across the contact breaker points. No reading indicates a faulty capacitor. Capacitor: The best method of testing a capacitor (condenser) is by substitution. Disconnect the original capacitor and connect a new one between the low-tension terminal on the side of the distributor and earth. If a new capacitor is needed, fit a new one complete with bracket, but if necessary unsolder the original bracket and solder it onto the new capacitor using as little heat as possible. Capacitor capacity is .15-.20 microfarads. 3:5 Removing and dismantling distributor (sedan and sports) To remove the distributor proceed as follows: 1 Rotate the engine slowly until the distributor rotor arm is opposite the brass segment in the distributor cap connected to No. 1 plug lead. This will provide a datum for replacement. 2 Disconnect the cable from the low-tension terminal on the side of the distributor body. Mark position of distri- butor on support. Release the distributor retaining nut and washer from the underside of the top flange of the distributor support and carefully lift away the dis- tributor. 3 Pull off the rotor arm. Remove the insulated terminal assembly from the side of distributor body. Release the contact breaker carrier plate retaining screws and con- denser flange screw from the outside of the distributor F500 49 body. Carefully lift out the contact breaker plate assembly. 4 Before further dismantling note the relative positions of the driving dog and the rotor arm driving slot at the top of the distributor cam spindle. The driving dog is offset and can only engage its driving spindle in one position. Then when the cam assembly is fitted to the centrifugal weights during reassembly the timing is not 180 deg. out. 5 Take out the cam lubrication felt pad recessed in the rotor arm housing on the end of the cam spindle. Remove the retaining screw, carefully disengage the springs and lift out the cam spindle. It should be noted that there is a small retaining ball and spring located in a drilling nearly at the top of the drive shaft spindle. Carefully lift away the weights. 6 Thoroughly clean all parts and inspect for excessive wear. The distributor cap must not be cracked or show signs of tracking. The cap terminals, rotor and contact breaker points can be cleaned with a very fine file. Emerypaper must not be used. If the clearance between the rotor and distributor cap segments exceeds .0118 inch both the rotor and distributor cap must be replaced. Inspect the contact breaker arm rubbing block for exces- sive wear and also the points for wear so that if the gap exceeds the last setting limit of .0209 inch and adjust- ment through the stationary contact carrier screw is no longer possible (see FIG 3:2), the contact breaker set must be renewed. If the distributor drive shaft side or vertical movement is excessive the distributor must be renewed. Weak centri- fugal weight springs or damaged weights must be renewed using original Fiat spares otherwise the auto- matic ignition advance characteristics could be altered. FIG 3:3 Ignition distributor in place on engine SPARK PLUG CABLES IGNITION COIL CABLE! DISTRIBUTOR CAP DISTRIBUTOR BODY GROUND CABLE CONDENSER DISTRIBUTOR SHAFT LUBRICATION FITTING DISTRIBUTOR SUPPORT-TO--CRANKCASE NUT [MOUNTING SCREW DISTRIBUTOR DISTRIBUTOR SUPPORT

timing Reassembly is the reverse procedure to dismantling but the following points should be noted: 1 Lubricate the parts of the centrifugal advance mecha- nism, the drive spindle and the part of the shaft which accepts the cam with Fiat VS oil. 2 Ensure that upon reassembly the slot in the rotor arm housing matches the distributor driving dog. Lubricate the felt pad in the rotor arm housing. 3 Fit the distributor back onto its support gently rotating the rotor arm so that the drive dog engages with the drive shaft mating flange. Provided the crankshaft has not been turned the rotor arm should finish up pointing to No. 1 cylinder segment in the distributor cap. Tighten the distributor retaining nut, refit the distributor cap and leads to the spark plugs and the LT lead to distributor body terminal. 4 Add a few drops of oil to the distributor shaft lubrication fitting (see FIG 3:3). 3:6 Removing and dismantling distributor (station wagon) The distributor is located towards the top rear of the engine and is bolted direct onto the crankcase rear cover as shown in FIG 1 :2. It is driven direct by a gear in mesh with a corresponding gear on the camshaft. The basic design of the distributor is the same as that for the sedan and sports engine, except that the distributor cap has been redesigned, there is a gear instead of the dog drive and no distributor support. To remove and dismantle the distributor proceed as previously described taking great care about marking the location of the distributor to rear cover and rotating the engine until No. 1 cylinder is on compression. This will ensure that reassembly is straightforward without loss of ignition timing. 50 3:7 Timing the ignition It is necessary to retime the ignition should the distribu- tor shaft or camshaft have been removed. To retime the ignition proceed as follows: 1 On the timing sprocket cover fit Fiat tool AP.5030/1 as shown in FIG 3:4. Ensure No. 1 cylinder is on the compression stroke with both valves closed. Rotate the crankshaft until the mark on the centrifugal filter cover lines up with the 10° mark on the fixture. This setting corresponds to a 10° static advance BTDC. 2 Check that the points gap is correctly set between .018 and .020 inch. Turn the distributor shaft until the rotor points in the direction of No. 1 segment in the cap and the points are just opening. 3 Without disturbing the distributor shaft, insert the lower coupling on its toothed end, install the support and tighten the locknut. Secure the distributor to the sup- port using the mounting screw. To check that the distributor is properly timed to the engine and the centrifugal automatic advance is operating correctly giving a total advance of 18° to 28° respectively proceed as follows: 1 Connect Fiat timing tester AP.5030 with a 220-volt- single-phase power outlet fitted with a good earth connection. It is important that the tester is earthed before it is allowed to operate. Also ensure that the tester earth terminal is connected to a bare metal part of the vehicle. 2 Remove No. 1 spark plug lead, insert the strobe light adapter and reconnect the spark plug lead. Using a piece of white chalk mark the TDC position on the centrifugal filter cover. 3 Start the engine and aim the strobe light beam towards the chalk mark drawn on the centrifugal filter cover. With the engine running slowly the mark on the centri- fugal cover must correspond with the first white line on the fixture (10°). Slowly increase the speed of the engine so operating the automatic advance and the chalk mark should move counterclockwise until at maximum speed it reaches the second white mark on the fixture. It should be noted that the ignition timing for the model 500 sports engine the static advance is 10°, an automatic advance of 12° giving a total advance at maximum engine speed of 22°. Should Fiat fixture AP.5030/1 not be available the advance position may be set as follows: 1 Turn over the engine until No. 1 piston is on the com- pression stroke with both valves closed. 2 Rotate the crankshaft clockwise until the reference mark cast on the centrifugal filter cover is set .5118 to .5512 inch ahead of the arrow cast on the timing sprocket cover. This will give a static advance setting of 10° BTDC. 3 Proceed as directed for ignition distributor timing and mounting described earlier in this section. 3:8 Sparking plugs The sparking plugs must be regularly inspected, cleaned and the electrode gap adjusted to a gap of .019 to .023 inch. The inspection of the deposits on the electrodes is par- ticularly useful because the colour and type of deposit

and may be used as a guide to engine tuning. Before the spark plugs are removed blow away any loose dirt from the plug recesses using a compressed air jet or tyre pump. Store the plugs in the order of removal ready for inspection. Examine the gaskets and if they are about half their thickness they may be used again otherwise they must be replaced. Inspect the electrode end of the plugs and note the type and colour of the deposit. Normally it should be powdery and range from brown to a greyish tan in colour. There will also be slight wear of the electrodes and the general effect described is one which comes from mixed periods of high-speed and low-speed driving. Cleaning and resetting the gap is all that will be necessary. If the deposits are white or yellowish they indicate long periods of constant-speed driving or much low-speed city driving. Again, the treatment is straightforward. Dry, black, fluffy deposits are usually the result of running with too rich a mixture. Incomplete combustion of the petrol air charge may also be a cause and this might be traced to a defect in the ignition system or excessive idling. Overheated sparking plugs have a white blistered look about the centre electrode and the side electrode may be badly eroded. This may be caused by poor cooling, wrong ignition timing or sustained high speeds under heavy load. To clean the sparking plugs effectively they should be cleaned using an abrasive blasting machine and tested under pressure once the electrodes have been reset. File these until they are clean, bright and the faces parallel and set the gap to .019 to .023 inch. Do not try to bend the centre electrode. Before replacing the plugs use a wire brush to clean the threads taking care that the electrodes are not touched. Thoroughly clean the spark plug in petrol, and dry using a compressed air jet or a tyre pump. If difficulty is found in screwing the plugs into the cylinder head by hand run a tap down the threads to clear away any carbon. If a tap is not available use an old sparking plug with crosscuts down the threads. Finally tighten the plugs to a torque wrench setting of 18 to 21 Ib ft. Sparking plug leads: The spark plug leads and the lead from the coil to the distributor cap must be regularly checked for cracking of the insulation and also correct seating in the distributor cap and coil top. It is recommended that silicone grease is smeared around the sockets before the leads are replaced to ensure no moisture may enter causing difficult starting. 3:9 The distributor driving spindle (sedan and sports engine) If for any reason, the driving spindle has been removed from its housing in the crankcase, it must be correctly meshed with the camshaft gear otherwise it will be impos- sible to set the ignition timing. 3:10 Fault diagnosis (a) Engine will not fire 1 Battery discharged 2 Distributor contact points dirty, pitted or maladjusted 3 Distributor cap dirty, cracked or tracking 4 Carbon brush inside distributor cap not touching rotor 5 Faulty cable or loose connection in low-tension circuit 6 Distributor rotor arm cracked 7 Faulty coil 8 Broken contact breaker spring 9 Contact points stuck open (b) Engine misfires 1 Check 2, 3, 4, and 7 in (a) 2 Weak contact breaker spring 3 High-tension plug and coil leads cracked or perished 4 Sparking plug(s) loose 5 Sparking plug insulation cracked 6 Sparking plug gap incorrectly set 7 Ignition timing too far advanced

4:1 4:2 4:3 Description Air outlet thermostat and shutter Tension adjustment 4:4 4:5 4:6 Heating system safety device Maintenance Fault diagnosis 4:1 Description Sedan: All the Fiat new 500 models covered by this manual are aircooled by the forced air circulation system from a centrifugal blower which is mounted on the generator output shaft. The blower fan has fourteen vanes which are arranged at various angles to reduce operating noise during high-speed operation. A specially designed cowling as shown in FIGS 4:1 and 4:2 conveys the air from the blower and distributes it to the various parts of the exterior of the engine. The main components of the air cooling system are as follows: 1 Air intake compartment at the rear end of the body. 2 An elbow pipe for the admittance of incoming air. 3 A flexible air pipe connecting the elbow pipe to the conveyor. 4 A spiral air conveyor which contains the centrifugal fan. 5 Distribution ducting for directing the air flow to various parts of the engine. 6 A bellows type thermostat is fitted to the cowling which operates a butterfly shutter controlling the air outlet from the engine which ensures control of the engine operating temperature. F500 53 When the shutter is in the open position, engine heated air is allowed to disperse to the outside of the engine cowling. With the shutter in its closed position, the air is recirculated in the engine cowling so ensuring a quick engine warm-up period. It should be noted that by operating the heater lever which is located on the centre tunnel at the rear seat, warmed air flowing out from the engine cowling is passed to the inside of the car for heating and demisting purposes. Station wagon: Refer to FIG 4:2 where it will be seen that as the engine is located on its side underneath the luggage compartment floor the ducting has been modified and the air intakes are located at the rear of the side windows. A linear blower is housed in the engine baffles and cowling and is attached to the drive end of the generator. The thermostat 'C' (see FIG 4:2) is located on the righthand side of the engine cowling and should start opening the engine heated air outlet shutter 'D' when the temperature of the air rises to 178-185°F and the shutter should be wide open when the air is at a temperature of 196-207°F.

Key to Fig4:1 A Engine cooling air intake B Carburetter air suction cleaner C Centrifugal fan and air conveyor D Oil pan cooling air passage E Warmed air admission hose to car interior F Engine air outlet control shutter, wide open position (at 178° to 189°F — 81° to 87° C) G Air outlet thermostat 54

Key to Fig 4:2 A Air intakes B Fan C Thermostat, engine air draft shutter control D Shutter enqine air draft E Carburetter air cleaner F Duct, warmed air-to-car interior G Lever, air-to-car interior valve control

COOLING AIR DUCTS FIG 4:3 Oil sump with blower cowling. Arrows indicate air outlets BLOWER SHAFT GENERATOR ARMATURE VENT TUBE FIG 4:4 Cooling blower mounted on generator shaft extension 4:2 Air outlet thermostat and shutter Refer to FIGS 4 :1 and 4 :2 where it will be seen that the thermostat is located on the righthand side of the engine cowling. The thermostat should start opening the engine heated air outlet shutter when the temperature of the air reaches between 158-165°F (178-185°F station wagon) and the shutter should be in the wide open posi- tion when the air has reached a temperature of between 178-189°F (196-207°F station wagon). When the engine cooling air control system is being inspected or serviced the following points should be noted: 1 Check that when the shutter is in the closed position the edge mates perfectly with the cowling seating. 2 Ensure that the shutter can swivel freely. 3 Check that the initial thermostat movement is between .0197 to .0394 inch. 4 Generally check the engine cowling for distortion, bad jbint sealing or cracks. 56 Key to Fig 4 : 6 1 Circular seat in cylinders 2 Head ducts 3 Pierced screws FIG 4:6 Diagram of the heating system safety device (sedan and station wagon) FIG 4:5 Location of cooling air outlet thermostat and shutter ENGINE COWLING. THERMOSTAT LINK AIR OUTLET SHUTTER SHUTTER RETURN SPRING 4:3 Tension adjustment, thermostat to shutter link: The tension may be varied by using the shims which are located between the upper shank of the thermostat and the cover shoulder washer. Before any adjustment is made ensure that the shutter is able to move freely and that the return spring has not stretched or fractured. Refer to FIG 4:5 which shows the location of the shutter and the return spring.

110F series sedan engines and later station wagon engines incorporate a modification to the cylinder head designed so that in the event of cylinder head gasket failure exhaust gases are expelled outside the engine and not leaked into the heating system. The safety device comprises a square section circular seat 1 (see FIG 4 :6) which is formed in the upper face of the cylinder, a special duct in the cylinder head and a pierced screw 3 for each cylinder. The system is so designed that the exhaust gases are released to the atmosphere from the circular seat in the cylinder via the duct 2 and the pierced screw 3. It should be noted that the screw 3 is also used for securing the conveyor. 4:5 Maintenance Due to the simple design of the air cooling system maintenance has been kept to an absolute minimum and should consist of the following checks: 1 Inspect all the air conveyor system joints and ensure that all the joint nuts and bolts are tight and that there is no distortion between two joint faces. 2 Check that the tension of the generator and fan drive belt is correct: with a hand pressure of approximately 22 Ib the belt should sag 13/32 inch. Adjust if necessary as detailed in Chapter 1. 3 Ensure that the shutter can swivel freely and that the spring is in a serviceable condition. 4:6 Fault diagnosis (a) Engine overheating 1 Generator and fan drive belt slipping 2 Shutter control thermostat defective 3 Shutter unable to swivel freely 4 Shutter return spring broken 5 Leaking joints in conveyor system F500 57

Dismantling and inspection of clutch cover Assembly and adjustment 5:1 Description New 500, 500D sedan and early station wagon: The clutch is a single plate dry disc type operating on the inner face of the flywheel. FIG 5 :1 shows a longitudi- nal cross section of the clutch as it is assembled in the power unit. A sheet metal clutch cover is attached to the flywheel by means of six screws and this encloses a clutch driven plate, the pressure plate and six springs. Three withdrawal levers are fitted so that the inner ends are attached to a carrier ring through which three springs hold the levers in place and the carrier ring in contact with the pressure plate, (see FIG 5:1). Release of the driven plate is obtained through a throw-out ring fitted with a central carbon thrust ring which acts on the withdrawal levers carrier ring. This is controlled by the clutch pedal through suitable linkage to the control fork. When the clutch pedal is operated, the throw-out ring, together with the carbon thrust ring is pushed towards the flywheel and this exerts a pressure on the withdrawal levers carrier ring and the lever inner tips. The lever outer tips lift the pressure plate so disengaging the clutch. F500 59 Each of the three withdrawal levers is mounted on a bolt together with an adjustment nut which is inserted in the pressure plate. The levers are kept in their location by a guide which is formed in the pressure plate. 500 F and L sedans and late station wagon: A single plate dry type clutch is fitted with a diaphragm pressure spring. This design of clutch differs from the con- ventional clutch because the pressure coil springs and throw-out mechanism components are replaced by a single diaphragm spring. The new system offers certain advantages which are as follows: 1 The load on the clutch pedal does not increase as the clutch disc lining wears but remains constant through- out the life of the clutch. 2 Due to the special shape and location of the diaphragm spring, which offers a constant force on the pressure plate throughout the clutch life, the clutch does not slip even though the driven plate linings may be worn. 5:5 5:6 5:7 5:8 Installation of clutch on flywheel Pilot bushing Withdrawal mechanism Fault diagnosis

adjusting the throwout lever. FIG 5:1 Clutch assembly longitudinal section (new 500, 500D sedan and early station wagon) 5:2 Removal and installation To remove the clutch unit from the vehicle proceed as follows: 1 Remove the engine (Chapter 1) or separate the gear- box from the engine as described in Chapter 6. 2 Remove the six screws and washers that secure the clutch cover to the flywheel and gently ease the cover assembly from the location dowels in the flywheel and lift away. This will also free the driven plate. 3 Carefully clean the driven plate and clutch cover using a compressed air jet. 4 To refit the clutch cover assembly to the flywheel ensure that the driven plate is assembled the correct way round as shown in FIG 5 :1 and place the cover onto the flywheel using the locating dowels. 5 To ensure that the driven plate is correctly centred use Fiat pilot A.62023 (see FIG 5 : 5) or a suitably sized mandrel. Tighten the clutch mounting screws diagonally a turn at a time to ensure correct location of the cover onto the flywheel face. Finally, tighten to a torque wrench setting of 5.8 to 7.2 Ib ft. 5 :3 Dismantling and inspection of clutch cover New 500, 500D sedan and early 500 station wagon : To dismantle the clutch cover assembly proceed as follows: 60 To assemble the clutch cover assembly proceed as follows: 1 Place the pressure plate complete with carrier ring bolts and springs on Fiat fixture 62038 (see FIG 5:2). 2 Fit the six pressure springs in their respective seats on the pressure plate. Insert the cups on the springs and replace the cover. 3 Compress the clutch cover, continually checking that the withdrawal lever supporting bolts are properly guided into their holes in the cover. Onto the bolts, fit the three withdrawal levers with their relevant nuts and washers. 4 Replace the carrier ring on the levers and hook up the retaining springs. 5 :4 Assembly and adjustment New 500 sedan 1 Place the clutch cover assembly on Fiat fixture A.62038 as shown in FIG 5 :6 and lock the cover using the three T-handles provided. 2 Release the withdrawal lever carrier ring springs and lift away the ring. 3 Unscrew the withdrawal lever fixing nuts on the bolts and lift out the levers and washers. Gradually slacken the three T-handles so relieving the pressure of the clutch springs. Remove the clutch cover, springs and lever mounting bolts. Carefully mark all the components to ensure that they are assembled correctly so ensuring that correct balance of the clutch unit is obtained. Inspection: Thoroughly clean all parts using a compressed air jet and proceed as follows: 1 Thoroughly check the springs for signs of overheating causing loss of tension and compare the effective length of the springs which when fitted new should have a length of .9646 inch under a load of not less than 43 Ib. If the spring length is less than the recommended dimension fit a complete new set of springs. 2 The length of the withdrawal lever carrier ring retaining springs should be checked which under a normal clutch load should be .7677 inch whilst the length'of the expanded spring under a load of 4.85 ± .44 Ib should be 1.1811 inch. If the springs show sign of heating or weakening a new set should be fitted. 3 Check the withdrawal levers and their bolts for exces- sive wear and fit new parts as necessary. 4 Inspect the pressure plate for an excessively ridged sur- face or signs of cracking. If the ridges are not too severe the face may be refaced by turning on a centre lathe. Also inspect the flywheel friction surface which may also be refaced providing that the ridges are not too severe. 5 Whenever the clutch driven plate linings are worn a new driven plate should be fitted. 6 Inspect the clutch shaft splines and these should not have a lengthwise clearance in excess of .0039 inch and side clearance of .0118 inch with respect to the driven plate hub. Ensure that the driven plate slides easily on the clutch shaft protruding from the rear of the gearbox differential unit as any plate drag may be the cause of difficulty in gear selection.

DRIVEN PLATE PRESSURE PLATE LEVER CARRIER LEVER BOLTS BOLT NUTS PRESSURE SPRINGS WITHDRAWAL LEVERS CLUTCH COVER LEVER CARRIER RING SPRING WASHER FIG 5:3 Clutch assembly installed on engine (new 500, 500D sedan and early station wagon) 61 F500 To check the correct operation of the clutch cover 500 sedan (110.F) late 500 station wagon : Inspection—diaphragm clutch: 5 Finally tighten down the cover assembly using the three T-handles and adjust the clearance between the carrier ring and its central shoulder by means of the three adjustment nuts.setting the withdrawal levers stroke to 0039 inch. Check this adjustment using Fiat gauge C.110 and when correct lock the adjustment nuts by peining to the lever bolts. 500D sedan and early station wagon: To assemble the clutch cover assembly proceed as described above but adjust the withdrawal levers as follows: 1 Secure the clutch cover assembly to Fiat fixture A.62038 with a ring .5413 to .5433 inch thick placed between the clutch cover plate and the pressure plate. 2 Adjust the height of the three withdrawal levers so that the lever tips are 1.9094 inch from the face of the Fiat supporting plate.

KeytoFig5:4 1 Clutch cover 2 Pressure plate 3 Clutch release flange plate 4 Diaphragm spring rings 5 Diaphragm spring retainer plate 6 Diaphragm spring 7 Clutch release flange X =1.463 ± .043 inches F = direction of clutch release flange movement 8 mm = .31 5 inch = release travel 5 mm = .197 inch = maximum allowance for driven plate lining wear 7.9 mm = .311 inch 62 5:5 Installation of clutch on flywheel Before assembling the clutch cover assembly and driven plate the following parts of the unit should be assembly proceed as follows: 1 Position the clutch cover assembly on Fiat fixture A.62038 with a spacer .311 inch thick between the cover and the plate. 2 Operate the clutch mechanism for four complete throw-out strokes by applying a load of at least 181 Ib on the release flange as shown by the arrow 'F' in FIG 5:4. 3 Check that with a withdrawal travel of .315 inch the pressure plate is displaced .071 inch. Also check that the distance'X' (see FIG 5 :4) is 1.463 inch ± .043 inch. Should the results obtained not compare with the manufacturers recommended figures, then the clutch cover assembly should be renewed. FIG 5:6 Fixture A.62038 for clutch disassembly, re- assembly and adjustment (new 500, 500D sedan and early station wagon) FIXTURE A. 62038 T-HANDLES CARRIER RING LEVER BOLT NUTS (LEVER ADJUSTMENT) FIG 5 : 5 Installing the clutch on flywheel using pilot A.62023 (new 500, 500D sedan and early station wagon) to centre the driven plate PILOT A. 62023 FOR DRIVEN PLATE CENTERING

1 Pressure plate—boss outer faces. 2 Clutch cover—withdrawal lever fulcrum. 3 Withdrawal lever stopnuts—contact face. 4 Withdrawal lever carrier ring — lever contact face. 5 Crankcase end pilot bushing lubricated with Fiat KG.15 grease. 6 Lubricate contact faces of driven plate and clutch shaft. To install the clutch assembly proceed as follows: 1 Ensure that there is no grease or oil on the faces of the driven plate or flywheel face and position with the raised part of the hub towards the transmission unit. 2 Locate Fiat tool A.70085 (diaphragm clutch) or A.62023 (coil spring clutch) or a suitably sized drift, through the driven plate hub and position in crankshaft pilot bushing. Gradually tighten the clutch unit mounting screws working diagonally and finally tighten to a torque wrench setting of 5.8 to 7.2 Ib ft. 5:6 Pilot bushing Whenever the clutch unit is being renewed or over- hauled it is essential that the crankshaft pilot bush is checked for excessive wear or damage. Also check that FIG 5:7 Side sectional view of clutch and throw-out mechanism - 500 Sedan (11OF), late Station Wagon. Value 1.5 mm (.059 inch) refers to the clearance to be obtained through the adjustment of clutch throw-out yoke rod F500 63 The withdrawal mechanism comprises a forked lever (see FIG 5:8), which is located in the clutch housing and 5:7 Withdrawal mechanism New 500 and 500D models: the spigot on the bush end is in a good serviceable con- dition. The maximum clearance between the clutch shaft spigot and the bush should not be greater than .0059 inch otherwise the pilot bush must be renewed. To remove the pilot bush use Fiat puller A.40006/1 /2 or a small universal internal bush and bearing removal tool. To fit a new bush use a suitably sized drift and drive the bush fully home and lubricate well with Fiat KG.15 grease. FIG 5:9 Clutch controls and adjusting mechanism LEVER RETURN SPRING ADJUSTABLE TIE ROD CLUTCH RELEASE LEVER NUT AND JAM NUT FOR TIE ROD CLUTCH RELEASE BOWDEN FIG 5:8 Clutch throw-out mechanism CLUTCH SHAFT LEVER-AND-SHAFT RELEASE RELEASE THRUST RING FORK-TO-THRUST FASTENERS RING CARBON RING WITHDRAWAL FORK CLUTCH

Key to Fig 5:10 1 Clutch throw-out yoke 2 Yoke return spring 3 Rod nut and counternut 4 Adjustable rod 5 Clutch throw-out onto this shaft the outer operating lever is attached by means of a key. A return spring connected to the outer operating lever is anchored onto the gearbox casing. When the clutch is in its normal position the spring keeps the central thrust carbon ring away from the withdrawal levers carrier ring. The carbon ring is pressed against the carrier ring by the throw-out ring which is connected to the forked lever as shown in FIG 5 :8. The clutch pedal must have free travel of 1"3/8 to 1"9/16 inch. Should any adjustment be necessary release the locknut from the adjustable tie rod and adjust the position of the tie rod until the correct adjustment is obtained. Tighten the locknut. 500F. L and later station wagon: The free travel of the clutch pedal should be 19/32 to 1"3/16 inch which corresponds to a clearance of .059 inch between the throw-out sleeve and the ring (see FIG 5 :7). Should any correction be necessary release the adjust- able rod locknut (see FIG 5:10), and reposition the adjustable rod using the rod nut until the recommended clutch pedal travel is obtained. Retighten the locknut. 5:8 Fault diagnosis (a) Drag or spin 1 Oil or grease on driven plate lining 64 (g) Driven plate fracture 1 Check 2 and 3 in (a) 2 Drag and distortion due to hanging gearbox in plate hub (f) Tick or knock 1 Worn first motion shaft spigot or bearings 2 Badly worn splines in driven plate hub 3 Release plate out of line 4 Faulty Bendix drive on starter motor 5 Loose flywheel (e) Rattle 1 Check 3 in (c) 2 Worn release mechanism 3 Excessive backlash in transmission 4 Wear in transmission bearings 5 Release bearing loose on fork (d) Judder 1 Check 1, 2 and 3 in (a) 2 Pressure plate not parallel with flywheel face 3 Contact area of driven plate linings not evenly distribu- ted 4 Bent first-motion shaft 5 Buckled driven plate 6 Faulty power unit mountings 7 Worn suspension mountings 8 Weak rear springs 9 Loose drive shafts (c) Slip 1 Check 1, 2 and 3 in (a) 2 Check 2 in (b) 3 Weak pressure springs or diaphragm spring (b) Fierceness or snatch 1 Check 1, 2 and 3 in (a) 2 Worn clutch linings 2 Misalignment between engine and gearbox first motion shaft 3 Driven plate hub binding on first motion shaft splines 4 Binding of first motion shaft spigot bearing 5 Distorted clutch plate 6 Warped or damaged pressure plate or clutch cover 7 Broken driven plate linings 8 Dirt or foreign matter in clutch

6:1 6:2 6:3 6:4 6:5 6:6 Description Removal of gearbox/differential unit Dismantling — gearbox Reassembly — gearbox Dismantling — differential and final drive Reassembly— differential and final drive 6:7 6:8 6:9 6:10 6:11 6:12 Final drive gear set adjustment Replacement of gearbox/differential unit Swing axle shafts and slip joints Gear shift control mechanism Modifications Fault diagnosis 6 :1 Description The gearbox and differential unit are housed in an aluminium alloy casing made up of two parts which split at the differential centre line. The output drive is trans- mitted by means of two half axle drive shafts coupled through wheel shafts and slip joints to the rear wheels (see FIG 6:1) The gearbox provides four forward-speeds and a reverse, the fourth-speed being considered as an overdrive. All gears except first and reverse gears, which are straight toothed sliding gears, are in constant mesh and have heli- cal teeth. No synchromesh is provided, gear engagement being completed by sliding shifter sleeves of the dog clutch type. The first-speed gear slides on the outside of the third and fourth shifter sleeve, whilst the reverse gear train moves on a fixed shaft. The clutch shaft is integral with the third, top and combined and first and second gear pinions, whilst the second gear pinion is splined at the front end. An internal splined coupling sleeve joins the clutch shaft and the input shaft and transmits the power from the engine to the gearbox. The mainshaft and differential drive pinion are combined together and besides carrying the constant mesh gears and the sliding first gear pinion, it also has attached the sliding sleeves and hubs. F500 65 The speedometer drive pinion is located at the front end. The gearbox/differential casing is attached to the engine by six studs which locate in the crankcase. The front of the unit rests upon the rubber mounted support which is secured to the body floor. The complete unit comprises three detachable parts made up as follows: 1 The support for the connection of the gearbox to the engine which also acts as part of the differential front end and clutch/flywheel housing at rear. 2 A central body which is divided into two compartments. The front compartment contains first, third, fourth and reverse gears with the primary shaft, layshaft and reverse shaft as well as the necessary gear selection striker rods and forks. The rear of this compartment also forms a half cover for the differential unit. 3 The gearbox casing cover, which contains the second- speed gears together with the relative fork, gear selection rod and speedometer drive gears. The central part of the casing is provided with a top inspection cover. The primary shaft is coupled to the clutch shaft through an internally splined sleeve and two pins which are retained by rings. The primary shaft together with the first, third and fourth driving gears form a cluster.

CLUTCH SHAFT SEAL PRIMARY SHAFT WITH 1st, 3rd AND 4th SPEED GEAR CLUSTER 2nd SPEED DRIVE GEAR PRIMARY SHAFT FRONT BALL BEARING PRIMARY SHAFT REAR BALL BEARING PRIMARY SHAFT-TO-CLUTCH i SHAFT JOINING SLEEVE JOINING SLEEVE LOCKRING SPEED SELECTOR LEVER CLUTCH SHAFT LAYSHAFT WITH BEVEL PINION SPEEDOMETER DRIVE GEAR 2nd SPEED ENGAGEMENT SLIDING SLEEVE 2ND SPEED DRIVEN GEAR LAYSHAFT FRONT BALL BEARING 3rd SPEED DRIVEN GEAR HUB FOR SLEEVE 3rd AND 4th/ SPEED ENGAGEMENT SLIDING SLEEVE 4th SPEED DRIVEN GEAR LAYSHAFT REAR ROLLER BEARING LAYSHAFT-TO-PINION ADJUSTMENT WASHER 1st SPEED AND) REVERSE SLIDING GEAR FIG 6:1 Gearbox-differential unit longitudinal section On the primary shaft extension outside the main central body is mounted the second-speed driving gear. The primary shaft is supported at both ends by ballbearings whilst the clutch shaft rotates in a bronze spigot bush which is press fitted into the end of the crankshaft. An oil seal is fitted in the clutch shaft passage seat in the connection support. The layshaft, together with the drive pinion of the differential unit is supported at the front by a ballbearing race. The layshaft carries the pinion adjustment shim, the fourth-speed driven gear and its bushing, the hub and relevant engagement sleeve for the third- and fourth- speed with first-speed and reverse-speed, the third-speed gear and bushing and, outside the casing the second gear and bushing, the hub with relevant second-speed engage- ment sleeve and the speedometer drive gear. The gears are operated by a gear selection lever mounted on the tunnel situated between the two front seats. This operates through a rod actuating the selector and shifting mechanism which is housed in the gearbox casing cover. Refer to FIG 6 :3 where it will be seen that the positioning of the striker rods is ensured by a spring-loaded ball- bearing. The risk of engaging two gears at the same time is eliminated by three rollers which slide in suitable slots machined in the rod (see FIG 6:4). The differential unit and the final drive gear train are housed in the two semi-covers which have previously been described, the final drive pinion being integral with the layshaft. The differential casing may be split into two halves. The bevel gear is fitted on one of the halves and is 66 secured by the same screws joining the two halves together. The differential side gears are internally splined into which are located the splined axle shaft ends which are able to slide by means of a specially designed slip joint. Two specially shaped rubber oil boots are inserted on the swing axle shafts and fit over the side gear extensions to ensure that there is no loss of lubricant or the ingress of dirt. The transmission and differential unit to suit the station wagon differs from the sedan in that the transmission to engine mounting plate and the bellhousing are modified to suit the engine repositioned on its side. 6:2 Removal of gearbox/differential unit: The complete unit may be removed whilst the engine remains in situ and to remove this unit proceed as follows: 1 Disconnect the battery positive cable and jack up the rear of the vehicle and place on firmly based stands. 2 Disconnect all control cables and wiring from the starter motor and the clutch lever. Remove the starter motor, the clutch lever reaction spring and the clutch cable support on the gearbox. 3 Remove the three bolts securing each of the driving shaft flanges to the flexible coupling at the wheel ends and carefully take out the inner spring. 4 Disconnect the shifter rod from the gearshift lever at the gearbox extension and also the speedometer drive cable. Remove also the flywheel undercover. Place a suitable support under the engine.

Gearbox gears, forks and striker rods K e y t o F i g 6 : 2 1 Rear roller bearing 2 Layshaft with bevel pinion 3 Front ballbearing 4 Front bearing plate 5 Bushing 6 Fourth-speed driven gear 7 Third- and fourth-speed sliding sleeve 8 First and reverse sliding gear 9 Sliding sleeve hub 10 Third-speed driven gear 11 Bushing 12 Bushing 13 Second-speed driven gear 14 Second-speed sliding sleeve 15 Second-speed sliding sleeve hub 16 Speedo drive gear 17 Reverse sliding gear 18 Reverse sliding gear shaft 19 Clutch shaft 20 Clutch shaft-to-primary shaft sleeve 21 Primary shaft rear ballbearing 22 Primary shaft with first and reverse, third and fourth gear train 23 Primary shaft front ballbearing 24 Second-speed drive gear 25 First gear fork 26 First and second gear striker rod with second gear fork 27 Reverse gear fork 28 Reverse gear striker rod 29 Third and fourth gear fork 30 Third and fourth striker rod 31 Gear selector and engagement lever SPRING GUIDE BUSHES REVERSE STRIKER ROD BALL SPRINGS POSITIONING BALLS STRIKER ROD BALL SPRING COVER PLATE 1st AND 2nd SPEED STRIKER ROD 3rd AND 4th SPEED STRIKER ROD FIG 6:3 Detail of gearbox section through striker rod positioning ball springs F500 67 5 Using a garage type hydraulic jack fitted with Fiat support Arr.2076 carefully placed under the gearbox- differential unit take the weight of the unit from the front mounting. Carefully remove the nuts securing the transmission unit to the engine and also the nuts that secure the transmission front support to the body brackets. 6 Carefully draw the transmission forwards away from the engine taking very great care that no weight is allowed to act on the clutch shaft until the end of the clutch shaft is clear of the flywheel and clutch cover assembly. Carefully lower the transmission to the floor. 7 Remove the front support together with its rubbers, drain the oil from the transmission unit and thoroughly wash the outside to remove all traces of dirt and grease and dry using a compressed air jet. The transmission is now ready for dismantling. 6:3 Dismantling— gearbox Before dismantling the gearbox ensure that the exterior is thoroughly clean and then proceed as follows:

STRIKER ROD LOCK ROLLER 1st AND 2nd SPEED STRIKER ROD 3rd AND 4th SPEED STRIKER ROD 3rd AND 4th SPEED STRIKER ROD LOCK - ROLLER REVERSE STRIKER ROD LOCK ROLLER REVERSE STRIKER ROD FIG 6:4 Detail of gearbox section through striker rod lock rollers 2nd SPEED DRIVEN GEAR 2nd SPEED ENGAGEMENT SLIDING SLEEVE 2nd SPEED FORK 1st AND 2nd SPEED STRIKER ROD REVERSE GEAR 3rd AND 4th SPEED STRIKER ROD REVERSE STRIKER ROD 2nd SPEED DRIVE GEAR SPEED SELECTOR LEVER FIG 6:5 Cross section of gearbox through striker rods with the indication of the gear selector lever angular displacement 68 AXLE SHAFT-TO-JOINT SLEEVE OIL BOOT RING GEAR FIG 6:6 Differential unit complete with axle shafts BEARING CONE ADJUSTER LOCK RING BEARING HOUSING DIFFERENTIAL CASE OIL BOOT RETAINER AXLE SHAFT 1 Remove the speedometer drive support together with its gears. Remove the front cover together with its gasket and the gear selection rod (see FIG 6:2). 2 Remove the lock ring and carefully slide the splined sleeve from the axle shafts. Remove the two roller bearing housings together with the relevent rubber boot fastening cover, the rubber boots and the adjuster ring lock rings. 3 Detach the transmission mounting on engine support and carefully remove the differential case assembly complete with the ring gear and axle shafts. 4 Open the fasteners and loosen all the shifter fork lock bolts. 5 Engage two gears at the same time so locking the input shaft and the mainshaft together. Remove the cotter pins and the nuts on the front end of the input shaft and the mainshaft. 6 Remove the retaining cover located on the lefthand side of the gearbox and carefully take out the shifter rod positioning balls and springs from their bores. Remove the upper shifter fork shaft and shifter fork, the middle shifter fork shaft together with its interlock pin and also the third and fourth gear shifter fork. Remove the plain washer and speedometer drive driving gear from the layshaft. 7 Remove the second gear engagement sliding sleeve together with the shifter fork, shifter fork shaft, sliding sleeve hub, second-speed driven gear with relevent bush and the first gear engagement fork. Take very great care not to drop the safety rollers whilst extract- ing the striker rods. 8 Remove the second-speed driving gear from the input shaft. Release the reverse shaft retaining screw and remove the shaft together with the reverse gear cluster. Remove the layshaft front bearing retaining plate. 9 Push the input shaft forwards until both ballbearing races are pressed from their seating and the coupling sleeve located between the input shaft and the clutch shaft can be reached from above. Carefully remove the retaining ring and a connection pin at the input shaft side of the coupling sleeve and carefully withdraw the clutch shaft and coupling sleeve. 10 Remove the input shaft front bearing race. Tilt the primary shaft in the casing and remove it from the gearbox housing. Remove the rear bearing. Carefully

1 Axle shafts 2 Sleeve retainment lockrings 3 Slip joint casings 4 Axle shaft-to-wheel shaft coupling sleeve 5 Differential case cover with bearing inner race 6 Side gears 7 Oil boot retainment cover 8 Side gear thrust ring 9 Idle pinion shaft 10 Idle pinions 11 Oil boots 12 Differential case with bearing inner race 13 Adjuster retainment ring 14 Bearing housings with retaining nuts and outer races 15 Idle pinion shaft retainment cup 1 6 Bevel gear withdraw the layshaft together with the final drive pinion and the roller bearing inner race from the rear. 11 From the inside of the gearbox casing carefully slide off the following parts from the mainshaft, the drive pinion adjustment shim, the third and fourth driven speed gears together with their bushes, the third- and fourth-speed hub and sliding sleeve, the first and reverse driven gear, and carefully drive out the front bearings and the bevel pinion rear bearing outer race. 1 2 Using a suitable press, drive out the drive pinion roller bearing inner race from the end of the mainshaft. Inspection of components: Before inspecting the various parts removed from the gearbox casing thoroughly wash all components and blow dry using a compressed air jet and then proceed as follows: 1 Thoroughly inspect the gearbox casing to ensure that it is not cracked and that the bearing seats are neither F500 69 worn or damaged so allowing the bearing outer ring to rotate during the normal operation. 2 Thoroughly check the ballbearings to ensure that they are in perfect condition and that both radial ply and axial play is not excessive. The maximum permissible bearing play is as follows: Front bearings of primary shaft layshaft: (a) Sideways .002 inch (b) Endwise .017 inch Primary shaft rear bearing: (a) Sideways .002 inch (b) Endwise .016 inch Hold the bearings firmly by the outer race and gently rock the inner race backwards and forwards. The sliding action produced should be free and silent. If any rough- ness is felt then the bearings must be renewed. Check the roller bearings by inspecting the condition of the rollers as well as the outer and inner races. Always fit new bearings if there is any doubt as to their efficiency.

centres and using a dial gauge ensure that there is no distortion. The out of true reading for bearing seats should be less than .0008 inch. Inspect the splines and ensure that the side and outerfaces are not indented. Replace if there are signs of wear. Also inspect the reverse shaft to ensure that it is perfectly smooth and not showing signs of pitting or partial seizure. 4 Carefully inspect all gear teeth for signs of excessive wear or damage. The contact faces must be smooth and show no signs of indentation marks. Also check that the backlash between the gears, when correctly mounted on the surface plate is not greater than .0039 inch. The maximum wear limit is .0079 inch. Check that the quick engagement front teeth of the second-, third- and fourth-speed gears are not damaged or excessively worn. Renew if there are signs of gearchange lever misuse. 5 Inspect the sliding sleeves and the relevent hubs, ensure that all the working surfaces are perfectly smooth. The clearance between the mating parts should not be greater than .0059 inch. Also inspect the meshing teeth and ensure that they are in good condition. 6 Check that the gear shifting selector forks are not dis- torted and that the striker rods freely slide in their seats in the gearbox casing. 7 Carefully inspect that all the oil seals are in perfect con- dition and if there is any doubt they should be renewed. 8 Inspect the striker rod locking balls and the safety rollers and ensure that they slide freely in their seatings. Also check the ball load spring efficiency and if this shows signs of weakness then it should be renewed. Any faults with these items will cause difficulty in engaging gears or autodisengagement during engine acceleration. 6:4 Reassembly—gearbox To reassemble the components to the gearbox ensure that all components are thoroughly clean and then pro- ceed as follows: 1 Press the pinion rear roller bearing onto the layshaft. Install the layshaft in the casing, and at the same time fit the adjustment shim, the fourth-speed driven gear together with its bush, the sleeve and hub for third and fourth gear engagement, the first-speed and reverse driven gear and the third-speed driven gear with its hub. 2 Install the front layshaft ballbearing securing the bearing retainment plate with the screws and finally lock the screws in position. 3 Insert the primary shaft together with the first, third and fourth driving gear train in the gearbox housing and slide the rear bearing onto the shaft. Push the input shaft forward to enable the clutch shaft coupling to be inserted in the rear and to be pulled up the primary shaft by means of the pin. Do not forget the retaining ring. 4 Slide the primary shaft backwards so pushing the rear bearing into its bore. Refit the front bearing onto the primary shaft. 5 On the layshaft insert the second-speed driven shaft and bush, the second gear sliding dog sleeve and the hub. Also insert the second-speed striker rod and the first-speed fork. Do not forget to fit the safety roller into its seating. 70 6 Slide the second-speed driving gear onto the primary shaft. Place the engagement fork on the third- and fourth-speed engagement sliding sleeve, and insert the striker rod, lock the relevent fork and fit the safety roller. 7 Insert the third safety roller and install the reverse shaft and insert the reverse gear cluster onto it and secure the shaft by tightening its block bolt. Install the reverse striker rod with its relevent fork. 8 Now refit the speedometer drive worm gear onto the layshraft. Tighten the nuts on the primary shaft and the layshaft, not forgetting to interpose the plain washer between the speedometer driving worm and the nut, to a torque wrench setting of 1 8.1 Ib ft to 25.3 Ib ft (primary shaft) and 28.9 to 36.2 Ib ft (layshaft). It is recommended that the input shaft and layshaft are locked together by engaging two gears at the same time. Finally, fit the splitpins. 9 Lock the shifter forks onto their shafts by tightening their respective bolts and bend up the special locking plates. Install the three positioning balls and relevant springs into their bores and refit the cover plate. 10 Install the casing cover together with its relevant gasket. This will enable correct positioning of the shift shaft lever so that it engages in the outer ends of the shifter shafts protruding from the gearbox casing. 11 Install the speedometer drive support on the gearbox casing and refit the upper gearbox cover. For subsequent differential operations and adjustments see Sections 6:6. 6:5 Dismantling—differential and final drive For the removal of the differential and final drive unit from the gearbox refer to Section 6:3. To dismantle the differential assembly proceed as follows: 1 Remove the retaining ring 2 (see FIG 6:7) retaining the splined sleeve 4 and slide the sleeve off the drive shaft. 2 Remove the retaining covers 7 and the oil boots all together with the bushes and seals, adjuster ring lock rings 13, adjuster rings housing 14, and bearing adjuster and roller bearing outer races. 3 Separate the differential housing halves by unscrewing and removing the six bolts that keep both the halves and the crownwheel together. It is advisable to mark the respective components to ensure correct matching upon reassembly. 4 Remove the differential pinion shaft retainer ring, also the differential pinions 10 by removing the shaft and withdrawing the two axle shafts 1. 5 Remove the differential side gears 6 and relevent thrust rings 8. 6 Using a press remove the differential bearing inner races from their seats on the carrier halves. 7 Thoroughly clean all parts and dry using a compressed air jet. Inspection: The components of the differential unit must be thoroughly inspected for correct operation and to deter- mine the presence of any wear, damage or other irregulari- ties. To check the items concerned proceed as follows: 1 Check thoroughly the idle pinion carrier shaft for signs

part is very heavily pressed when the vehicle is negotia- ting a corner. If the clearance to the idle pinions exceeds .0059 inch the shaft must be renewed. 2 Inspect the ring gear and pinion seat, the side gears.and the idle pinions for correct meshing. This will be shown up by white marks on the sides of the gear teeth. Check that none of the teeth are broken, chipped or exces- sively worn and if any part is suspect then it must be renewed not forgetting that the ring gear and pinion come as a matched pair. 3 Inspect the condition of the ball and roller bearings, the rollers and balls and working faces must not show signs of pitting wear or cracking and if any part is suspect then the race must be renewed. 4 Check that there is not any undue wear on the faces of the thrust rings. Any slight indentations may be evened out using a fine oil stone but if the damage is excessive then new rings or oversize rings must befitted as neces- sary. Thrust rings are supplied as service spares in the following thicknesses. Standard .0394 inch Oversize .0512-.0591 inch 6:6 Reassembly—differential unit To reassemble the differential case proceed as follows: 1 Press onto the differential half housing which carries the ring gear one differential bearing inner race ensuring that it is pushed fully home onto its seating. Install the thrust ring and side gear (see FIG 6 :7). 2 From the inside of the case insert the axle shaft com- plete with pivot and runners that form the slip joint. Also install the idle pinions and carrier shaft. Position the ring gear onto the housing half and install the differential pinion shaft retainer ring. 3 Press the other differential bearing inner race onto its seating on the left differential housing half and replace the left axle shaft complete with slip joint. 4 Join the two case halves together and tighten the retaining screws and also the retaining screws of the ring gear to a torque wrench setting of 23.1 Ib ft. Secure all screws by bending up the lockplates. 5 Press the differential bearing outer races into their seatings in the bearing housings and also fit the oil seals. Also install the bearing housings over the driving shafts together with the adjuster rings. 6 Install the differential unit assembly into the final drive housing front half and bolt the rear half onto it. Tighten the six mounting nuts to a torque wrench setting of 27.5 Ib ft. Finally place the bearing housings in their seats and tighten the mounting nuts to a torque wrench setting of 13 lb ft. It should be noted that after the gearbox has been over- hauled the complete differential unit should only be in- stalled after the drive pinion depth adjustments has been carried out. 6:7 Final drive gear set adjustment The installation and adjustment of the final drive gear set requires special care otherwise the unit may have to be dismantled again for further adjustment. So as to establish the correct mesh of the two gears, their relative position is accurately set during initial assembly at the factory. F500 71 Refer to FIG 6 :8 where it will be seen that two numbers are stamped on the pinion shaft near to the threaded end, the upper number is the matching number which should also appear on the crownwheel. The lower number indi- cates the positive or negative deviation from the theoretical distance between the centre line of the ring gear and the pinion face. It is this number which must be taken into account when calculating the adjusting shim thickness which has to be fitted between the rear roller bearing and the fourth-speed gear on the layshaft. The formula from which the adjusting shim thickness can be calculated is as follows: S=A—(B + C) Where S=shim thickness. A= distance between the front bearing inner race and the centre line of the ring gear. B = distance of the drive pinion face to the ring gear centre line. C=the total of the widths of the third-speed gear bush, third- and fourth-speed hub, fourth-speed gear bush and rear roller bearing inner race fitted onto the mainshaft It should be noted that 'A' is the total of half the diameter of the differential bearing housing seat which is in actual fact 41.00 mm, and the distance measured between the front bearing inner race and the differential bearing housing seat. The last dimension will have a minimum manufactu- ring limit of 150.54 mm. Any deviation from this value must be determined and considered when determining the total shim thickness 'S'. A= 150.54 + 41.00 + a (deviation) To determine deviation 'a' Fiat tool A.62036 should be assembled to the gearbox casing as shown in FIG 6:9 and to take the reading proceed as follows: 1 Assemble the front ballbearing and its retainer into the gearbox housing and tighten the retainer bolts. 2 Hold the gearbox housing in the vertical position with the differential side upwards and insert Fiat tool A.62036 carefully from above into the bearing bore and lock it firmly by tightening the knurled nut. 3 Using Fiat dial gauge C.689 which has been previously zeroed on a surface plate should next be mounted onto the top of Fiat tool A.62036 with its pointer resting on the lowest position of the differential bearing hous- ing bore as shown in FIG 6:10. To obtain the lowest point move the pointer to both sides of the bottom dead centre position so as to obtain the maximum reading. The distance 'B' in the formula for calculating the shim thickness is designed to have a lower manufacturing limit of 75 mm. Any deviation 'b' is stamped on the drive pinion. Therefore to calculate the value of 'B' B= 75+ b (deviation) The distance 'C' in the formula for calculating the shim thickness is designed to have a lower manufacturing limit FIG 6:8 Layshaft with final drive pinion. The arrow points to the number (14) for correct mating with ring gear and to the centesimal figure (—10) for accurate mating position of pinion and gear

'A' Distance between pinion front bearing inner shoulder and the axis passing through the differential bearing housing centre 'a' Difference between the minimum value called out on drawing (5.9268inches — 150.54mm) and actual machining value of the distance between pinion front bearing inner shoulder and differential bearing housings DIAL GAUGE C.689 TOOL A.62036 FIG 6:10 Reading value a on gauge C.689 to determine drive pinion shim thickness 72 The procedure for adjustment of the final drive gear set is exactly the same as for the new 500 model except of 115.64 mm. Fiat tool A.62037 as shown in FIG 6:12 used in conjunction with the dial gauge can now be used to measure the deviation 'c' from the lower manufacturing limit as follows: 1 Place the dial gauge on a stand on the surface plate and place Fiat tool A.62037 on the plate as shown in the FIG 6:11. 2 Carefully slide onto the Fiat tool the following items, third-speed driven bush, third- and fourth-speed gear engagement sleeve, hub, fourth-speed driven gear bush and drive pinion roller bearing inner race. Set the dial gauge to zero using Fiat tool A.62037 as the datum and then rest the dial gauge plunger on the roller bearing inner race and take a reading at the dial as shown in FIG 6 :11. This reading will represent 'c' which can now be used in the formula. C = 1 1 5 . 6 4 + c (deviation) Once the values of A', 'B' and 'C have been found as detailed above we can now insert the values into the basic formula S = A—(B + C) which will now give us: S = 1 50.54 + 41.00+ a — (75+ b +115.64 +c) which can be simplified by using algebra to give us the following formula: S = 0.90 + a —(b + c) Shims are supplied in the following thicknesses, .0039 inch and .0059 inch. One or more shims should be used to make up the required shim thickness. Adjusting final drive gear set (500D, and 500F sedan and early station wagon): FIG 6:11 Setting dial indicator to zero on tool A.62037 TOOL A.62037

Key to Fig 6:12 1 Bevel pinion rear roller bearing inner race 2 Bush, fourth-speed driven gear 3 Hub, third- and fourth-speed engagement sleeve 4 Bush, third-speed driven gear 'C Total height of items 1, 2, 3 and 4 which must be mounted on final drive pinion 'c' Difference between actual height C and the minimum drawing call-out 4.5527 inch represented by tool A.62037 that the new Fiat tools are used to determine shim thick- ness as detailed below: S = 0.90 + a — (b + c) Where S = shim thickness 0.90 = standard coefficient a = value of reading on the dial indicator A.95690 applied to fixture A.70036 as shown in FIG 6:13. b = value stamped on pinion stem as shown in FIG 6:8. c= value read on the dial indicator corres- ponding to the difference between height of Tool A.70037 as shown in FIG 6:14, and the sum of the thicknesses of the items to be installed in pinion and included between front bearing inner shoulder and rear bearing outer shoulder. Ring gear clearance and differential bearing pre- load : To enable the correct ring gear tooth clearance to be ascertained use Fiat tool A.62039 together with a dial gauge. The support for dial gauge should be fixed into the two lower bolt holes of the flywheel housing and the pointer of the dial gauge adjusted so that it is located through the clutch shaft hole in the final drive housing so resting on a ring gear tooth (see FIG 6:15). Then proceed as follows: 1 During reassembly the differential bearing nuts should not have been screwed fully home to the differential F500 73 bearing outer races when installing into the final drive unit. These should now be carefully screwed in until they are in gentle contact with the bearing races. 2 Slide Fiat tool A.62040 over one of the drive shafts and using Fiat tool A.62041 lock the drive shaft to the differential housing thus preventing the drive pinion from rotating. 3 Gently turn the drive shaft which should now be locked to the ring gear and note the movement of the dial gauge indicator. This will show the tooth clear- ance. When the clearance is correctly adjusted the FIG 6:14 Reading value c on dial indicator Key to Fig 6:13 1 Dummy pinion, tool A.70036 2 Support with dial gauge, tool A.95690 FIG 6:13 Diagram showing the position of tools for determining the value of a

TOOL A. 62040 PIN WRENCH A. 52022 FIG 6:15 Adjusting ring gear-to-pinion backlash and differential bearing play, using special wrench A.52022 reading on the dial gauge should be between .0031 to .0047 inch. The actual clearance is adjusted by screwing in one adjusting nut and screwing out the other by the equivalent amount using Fiat spanner A.52022 as shown in FIG 6:15. 4 Remove Fiat tool A.62041 and using Fiat support A.62040 mount the special dynamometer A.95697 and adaptor on the axle shaft. Rotate the axle shaft several turns so seating the bearings and then check using the dynamometer the rotation torque. 5 If necessary tighten or slacken the adjusters until the specified torque of 1.01 ± .07 lb ft is obtained. This operation must be very carefully carried out because if one adjuster is set differently with respect to the other, a variation in ring gear to pinion backlash may take place, resulting in a variation of rotation torque. After any adjustments always recheck on the ring gear to pinion backlash and if necessary readjust and then repeat the rotation torque check. 6 Finally check the tooth contact between the pinion and ring gear as detailed in the following instructions: Check and adjustment of tooth contact between pinion and ring gear: 1 Carefully apply to the ring gear teeth a thin layer of engineers' blue and gently rotate the differential whilst holding the axle shaft firmly but allowing them to slip slightly so as to have the unit working under load conditions. 2 A contact impression will be left on the ring gear teeth and the contact will be correct when the drive pinion tooth contact pattern is evenly distributed on the ring gear teeth as shown in FIG 6:16. Should the tooth contact be incorrect the following observations should be noted. Excessive contact on tooth flank. Too deep meshing — move pinion out from ring gear by reducing thickness of shim. Excessive contact on tooth heel. Too slight meshing—move pinion in towards ring gear by increasing thickness of shim. 74 6:8 Replacement of gearbox—differential unit Installation is the reverse procedure to removal of the unit from the vehicle as described in Section 6:2. However, the following points should be noted: 1 Ensure that the clutch driven disc hub is correctly aligned with the clutch shaft pilot bush. 2 The complete transmission unit should be carefully pushed towards the engine and the clutch shaft inserted into the driven disc hub splines and finally home into the pilot bush. Extreme care must be taken to ensure that no weight is placed on the clutch shaft otherwise distortion may take place. 3 Carefully connect the gearbox rear housing to the engine crankcase by using the studs, two of which have special location dowels fitted. Screw home finger tight the gearbox/differential to body to front support mounting screws inserting the fibre washers. Lower the hydraulic garage jack and pull it away from underneath the vehicle. Screw in the four lower mounting nuts and tighten to a torque wrench setting of between 18.1 to 21.7 Ib ft.Finally tighten the front support screws. 4 Reconnect the gear shift control rod and the speedo- meter drive cable. Insert the springs between the axle shafts and wheel drive shaft and tighten the three mounting screws of each splined sleeve on the flexible joint to a torque wrench setting of 20.3 Ib ft. 5 Refit the flywheel housing cover. Replace the starter motor together with its relevant cover and tighten the two mounting nuts to a torque wrench setting of 18.1 to 21.7 Ib ft. Reconnect the starter control rod, the two starter cables, the clutch control tie rod and hook up the return spring and secure the clutch control cable retainer bracket to the gearbox casings. Reconnect the cable to the battery positive terminal post 6 Lower the vehicle to the floor gently and then give a thorough road testing. 6 :9 Swing axle shafts and slip joints Description: The two axle shafts are connected to the differential unit through specially designed slip joints which allow the shafts to swing and slide in the splined housing in the differential side gear. At the other end, the axle shafts are connected to the wheel drive shaft flexible joints using a sliding sleeve. Excessive contact on tooth face. Too slight meshing—move pinion in towards ring gear by in- creasing thickness of shim. Excessive contact of tooth toe. Too deep meshing —move pinion out from ring gear by reducing thickness of shim. With all the above detailed cases, to adjust the pinion by replacing the shim, the differential unit and drive pinion shaft must be dismantled. This means that when the unit is reassembled after the necessary adjustments have been made, the backlash and bearing rotation torque must be repeated.

Excessive contact on tooth flank: move pinion out from ring gear by reducing thickness of shim. Excessive contact on tooth toe: move pinion out from ring gear by reducing thickness of shim. FIG 6 :16 Ring gear to pinion tooth contact F500 75 move pinion in towards ring gear by increasing thickness of shim. Excessive contact on tooth face: move pinion in towards ring gear by increasing thickness of shim. Excessive contact on tooth heel:

BOOT MOUNTING SCREWS GEARSHIFT LEVER BOOT GEARSHIFT LEVER FIG 6:17 Location of gearshift lever on control passage tunnel Repair and inspection : Whilst servicing the assembly thoroughly check the condition of the slip joints sliding surfaces and the housing in the differential side gears. If, due to wear, the clearance is greater than .008 inch the slip joints should be renewed or in extreme cases the differential side gears as well. Also check the clearance between the slip joint pivots and runners and if it is found to be excessive the axle shafts must be renewed as well as the runners as the joint pivot is not supplied as a service spare part. The axle shaft to sliding sleeve spline clearance should not exceed .006 inch. Check that the sliding sleeve snap ring is a snug fit in its seating groove on the shaft. Whenever the vehicle is being serviced the condition of the boots, bushings and oil seals should be checked and any damaged parts renewed. 6:10 Gear shift control mechanism Should difficulty be experienced in obtaining correct gear selection then the gear shift control mechanism should be adjusted as follows: 1 Remove the screws fixing the cover to the tunnel and raise the cover to the top of the gear shift lever stem. 2 Slacken the lever support mounting screws and push the support forward if first- and third-speed engage- ment is incorrect or backwards if second-, fourth- and reverse-speed engagement are incorrect. Finally tighten the mounting screws. Refit the gear shift lever boot. Removal: To remove the gear shift control mechanism from the car proceed as follows: 1 Unscrew the gear shift control lever knob and the boot fixing screws and slide the boot from the gear shift lever. 76 Key to Fig 6:18 1 Hand lever 2 Inner lever 3 Lever return spring 4 Hand lever spring 5 Ball seat 6 Inner lever-to-rod mounting screw 7 Gearshift control rod FIG 6:18 Gearshift control mechanism 6:11 Modifications Various design modifications are incorporated on the 500 sedan (110F) and the late version of the 500 station wagon. These are shown in FIGS 6:19 and 6:20, The gear shift handlever is removed by releasing the lever to support mounting self-locking nut. Check that the lever ball and socket are in good condition and not badly pitted or worn. The inner lever return spring and the hand lever spring should be checked for weakness which, if apparent, should be renewed. Reassembly is the reverse procedure to dismantling. Dismantling and inspection: 2 Remove the screws fixing the assembly to the tunnel. Remove the tunnel front cover. 3 Disconnect the gear shift control rod at the gear engagement control lever and pull out the assembly from the front end.

Key to Fig 6:19 1 Reverse shifter shaft 2 Third and fourth shifter shaft 3 First and second shifter shaft 4 Countershaft pinion (and ring gear) 5-7 Transmission-differential case 6 Housing 8 Clutch shaft FIG 6:20 End sectional view of transmission — differential assembly The items having undergone design modifications, besides and final drive gears 2 Seal 3 Bushing 4 Oil those shown in Fig 6 :19 are the following: 1 Differential case boot 5 Axle shaft 6 Joint casing 77 F500

have been previously described. 6:12 Fault diagnosis (a) Noisy transmission 1 Excessive backlash of gears in mesh due to gear wear 2 Gears, bearings or gear bushings damaged 3 Shafts misaligned or out of centre due to loose mount- ing nuts 4 Dirt or metal chips in the lubricant 5 Insufficient oil level in transmission case (b) Transmission jumps out of gear or gear shifting is irregular 1 Improper shifting 2 Gear shift lever mounting bracket out of adjustment 3 Incorrect assembly or damage of striker rod positioning balls and springs 4 Striker rod rollers worn or assembled incorrectly (c) Oil leakage 1 Overfilled transmission case 2 Front extension, upper cover and clutch housing nuts loose 3 Speed selector and engagement lever seal at front extension damaged 4 Faulty bellhousing gasket 5 Gaskets, upper cover-to-case, front extension-to-case, damaged 6 Damaged axle shaft boot or seal (d) Transmission shifts hard 1 Defective link of gear shift lever to internal front lever 2 Internal front lever rubber bushing and plates damaged 3 Speed selector and engagement lever control rod twisted 4 Control rod-to-speed selector and engagement lever joint damaged 5 Speed selector and engagement lever worn 6 Striker rods binding in casing 7 Sliding sleeves and gears bound in their seats due to the presence of dirt in splines 8 Improper quality of transmission lubricant 9 Misadjusted clutch linkage and clutch make de- clutching impossible 78

7:1 7:2 7:3 7:4 Description Removal of rear suspension assembly Servicing swinging arms Coil springs 7:1 Description The rear wheels are independently sprung by means of coil springs and V-shaped swinging arms acting on coil springs and telescopic double acting hydraulic shock absorbers. The swinging arms are mounted at their inner ends on 'estendblocks', the coil spring is fitted at the outer end of the swinging arm. At the wheel end of the suspen- sion arm is attached a steel pressing to which the brake backplate and wheel bearing housing are bolted so forming a swinging unit to which is attached the road wheel. The inner pivots are so located vertical wheel move- ments do not influence the drive shaft length which means that there is no need to fit a splined joint at the wheel end. Two taper roller bearings which are separated by a specially designed collapsible spacer are located in the rear wheel bearing housing and this carries the axle shaft. The outer end of the axle shaft is flanged and it is to this flange that the brake drum is bolted. The splined inner end carries a rubber cushioned coupling to which the drive shaft flange is attached. 7:2 Removal of rear suspension assembly 1 Jack-up the vehicle and place on firmly based stands. Remove the road wheel on the side from which the suspension unit is to be removed. F500 79 7:5 7:6 7:7 7:8 Installation of rear suspension assembly Checking and adjusting rear wheel toe-in Modifications Fault diagnosis 2 Using a garage hydraulic jack support the swinging arm to facilitate the removal of the upper shock absorber mounting nut which is located inside the vehicle on the floor. To gain access to the nut remove the rear wheel housing linings. 3 Unhook the parking brake shoe control lever return spring. 4 Remove the three screws securing the drive shaft flange to the flexible coupling. Pull back the sleeve and remove the inner spring. 5 Remove the brake fluid reservoir cap, remove the filter and plug the delivery hole in the brake fluid reservoir and disconnect the flexible brake pipe from the bracket on the body floor. 6 Disconnect the parking brake control tie rod by first removing the cotter pin and removing the cable eye from the pin on the shoe control lever. Release the cable adjustment nuts and free the cable from the fairlead on the swinging arm. 7 Using the hydraulic jack carefully lower the swinging arm, fully retract the shock absorber by pushing in the outer cylinder and carefully pull out the coil spring together with its mounting rubber rings. 8 Remove the self-locking nut securing the swinging arm to the internal support welded on the floor. Extract the mounting pin and note the number and arrangement of shims between the bushings and the bracket. This will facilitate reassembly.

Key to Fig 7:1 1 Brake shoe control cable and sheath 2 Coil spring 3 Oil boot 4 Axle shaft 5 Bumper 6 Flexible joint 7 Swinging arm 8 Cable adjusting nut 9 Swinging arm-to-front bracket mounting pin 10 Swinging arm front bracket-to-underbody mounting screw 11 Engine front support crossmember 12 Swinging arm rear self-locking nut 13 Shock absorber-to-swinging arm lower nut 14 Sleeve screws 15 Axle shaft-to-flexible joint sleeve 9 Remove the three swinging external support fixing bolts securing the outer suspension arm bracket to the vehicle floor and remove the rear suspension assembly. Remove the special rubber pad located between the support bracket and the vehicle floor. 7:3 Servicing swing arms Dismantling: 1 Remove the cotter pin and release the nut fixing the flexible joint to the wheel shaft. Remove the plain washer and the joint. 2 Using Fiat tool A.40005.1.9 or a universal two-leg puller, remove the wheel shaft and brake drum. Extract the two oil seals and both the outer and inner bearing inner rings, thrust ring of the joint and the resilient spacer. 3 Using Fiat tool A.6511, remove the two bearing outer rings. 4 Disconnect the brake hydraulic line at the wheel cylinder and remove the swinging external support. The bearing housing and brake housing flange may then be removed. Inspection : Thoroughly clean all the parts and install the swinging arm on Fiat fixture A.66064 as shown in FIG 7:4. If the 80 swinging arm has not been distorted its installation on the fixture should be straightforward. Tighten the clamp screws 1 (see FIG 7:3) on the road wheel brake drum, connect the swinging arm inner member to the seating 2 on the fixture and finally fit the swinging arm external support holes on the fixture pins 3. Should difficulty be experienced in either one of these three operations then this is an indication that the swinging arm is distorted and should be straightened or a new assembly fitted. If this check is satisfactory proceed as follows: 1 Check that the 'estendblocks' are a snug fit in their respective seatings in the swinging arm and that the mounting pin slides in freely without excessive play. To renew the 'estendblocks' use Fiat tool A.66056 which is suitable for both their removal and installation. 2 Check that the inner and outer bearing outer rings have no play in their seatings and that the rollers and cages are not broken, cracked, show signs of overheating or are worn. 3 Ensure that the oil seals fit snugly on the wheel shaft, also on the joint spacer or shoulder ring and on the hub seats. If the oil seals should show any signs of wear then these should be renewed. 4 Inspect the resilient spacer for signs of hair line cracks, which if not evident the spacer may be used again as it is not permanently distorted during assembly. Should, however, new bearings or bearing housings be fitted it is considered good practice to fit a new spacer.

5 Check the mating surface of the bearing inner rings on the wheel shaft and ensure that it is perfectly smooth. Also check that the shaft splines to flexible joint splines are not distorted or show signs of excess wear. The maximum permissible wear backlash is .0059 inch. 6 Ensure that the flexible joint is not damaged where the rubber is bonded to the metal. If signs of strain are indicated a new joint must be fitted. F500 81 Reassembly: Reassembly of the swinging arm unit is the reverse procedure to dismantling. The following points should be noted: 1 Always use Fiat tool A.66056 to install 'estendblock' on the swing arm. 2 The mounting nuts for the bearing housing to the brake housing flange should always be tightened to a

and adjustment Key to Fig 7:3 1 Clamp screws, securing wheel shaft on fixture 2 Alignment bracket, swinging arm member check-up 3 Nut, to secure swinging arm external support on fixture stud 4 Swinging arm external support centring pins A B C D FIG 7:4 Adjusting right rear suspension swinging arm on fixture A.66064 Key to Fig 7:4 A and B Swinging arm external support adjustment shims C and D Swinging arm internal support adjustment shims torque wrench setting of 43.4 Ib/ft. 3 During assembly the bearings must be packed with Fiat MR grease, taking care not to overpack as this can result in early bearing failure. 82 4 If the axle shaft to flexible joint tie sleeve has been removed, the mating splines must be coated with Fiat B2G grease on re-installation. 5 Preload the wheel bearings and adjust the swinging arm as described later on in this section. Wheel bearing adjustment: To ensure a long bearing life due to correct initial adjustment the ballbearings should be preloaded and to do this proceed as follows: 1 Tighten the wheel shaft nut gradually so that the rotation torque does not exceed .36 Ib/ft. 2 To check the rotation torque install Fiat tool A.95697/2 on the wheel drum and insert the shank 2 (see FIG 7:5) of dynomometer A.95697 in the support and securely hold the lever 3. Move the needle 5 to register .36 Ib/ft on the dynomometer scale as shown in FIG 7:5 and using the operating lever 6 rotate the dyno- mometer and the wheel shaft some turns in a clockwise direction. During rotation check that the needle 5 does not exceed the setting index 4. Should the rotation torque prove to exceed .36 Ib/ft, this will indicate a 4 3 1 6 5 2 FIG 7:5 Bearing rotation torque dynamometer K e y t o F i g 7 : 5 1 Dynamometer A.95697 2 Dynamometer shank to insert in item A.95697/2, fitted to wheel drum 3 Dynamometer grip lever 4 Rotation torque setting index 5 Adjustable needle 6 Dynamometer operating lever Oil Sump Wheel Plane HALF TRACK FIG 7:6 Position of rear suspension and of vehicle for rear wheel toe-in inspection and adjustment Key to Fig 7:6 ~ 168 mm = 6.61 inch 567,5 ± 1 , 5 = 22.342 inch ± .059 inch

and fit a new resilient spacer. Repeat the rotation torque test. Swinging arm adjustment: To adjust the swinging arm use Fiat fixture A.66064 as shown in FIG 7:3 and proceed as follows: 1 At points A and B as indicated in FIG 7 : 4 between the 'estendblock' and the swinging arm to body front mounting bracket fit three shims on each side. To ensure that the shims are correctly centred use Fiat alignment bar A.66057. 2 Whilst removing the alignment bar, carefully slip in the mounting pin and screw on the nut. Once the rear wheel geometry adjustment has been completed this nut should be tightened to a torque wrench setting of 43.4 to 50.6 Ib ft. 3 At points C and D (see FIG 7:4), insert the number of shims required to fill in the gap between the 'estend- block' and the two fixture shoulders. Having deter- mined the number of shims required both at locations C and D, these must later be fitted between the 'estendblock' and the shoulders on the swinging arm to body mounting bracket. 7:4 Coil springs The coil springs should be thoroughly cleaned and all traces of rust removed. Inspect the spring coils for hair line cracks, which if evident, a new pair of springs must be fitted to ensure correct vehicle height and stability. Check the free height and the height under loading of the coil springs and these must correspond to the figures quoted in Technical Data. 7:5 Installation of rear suspension assembly To replace the rear suspension assembly proceed as follows: 1 Insert the swinging arm inner end in the mounting bracket which is welded onto the body floor. Place between the 'estendblock' and bracket the number of adjustment shims as previously determined using Fiat fixture A.66064 as shown in FIG 7:4. Insert the Fiat alignment bar A.66057 through 'estendblock' and shims, aligning them with the holes in the mounting bracket. Firmly hold the entire assembly using a garage hydraulic jack if necessary, and carefully remove the alignment bar and at the same time ease in the mounting pin. Secure the nut which once the rear wheels geometry has been checked must be tightened to a torque wrench setting of 43.4 to 50.6 Ib/ft. 2 Screw in finger tight the three swinging arm external bracket to body floor mounting screws together with the plain and spring washers. The screws will have to be tightened to a torque wrench setting of 28.9 to 36.2 Ib/ft once the rear wheel geometry has been adjusted. 3 Carefully insert the coil spring, lower insulator ring onto the swinging arm, insert the spring on the shock absorber which should be previously secured to the arm and position the spring onto its seat on the arm. Place the upper insulator ring onto the spring, raise the suspension assembly using a garage hydraulic jack and insert the spring onto its seating under the body floor. F500 83 4 Ensure that the shock absorber to floor rubber ring has been correctly fitted and extend the shock absorber until its upper mounting pin protrudes into the vehicle through the hump in the floor panel. Secure the shock absorber by its mounting nut and lockwasher having first inserted the rubber ring and plain washer. 5 Refit the rear wheel housing in place, reconnect the brake line to the connection on body floor and remove the plug from the output hole in the brake fluid reservoir. Bleed the hydraulic brake system as described in Chapter 10. Key to Fig 7:8 k Distance of centre rear bracket, for jacking up the vehicle, from floor level (8.90 inch) Half-track = 22.264 inch ±.059 inch FIG 7:8 Position of rear suspension for rear wheel toe-in inspection and adjustment ('500 Station Wagon') FIG 7:7 Adjusting rear wheel toe-in angle Key to Fig 7:7 Rear wheel plane must be perpendicular to ground and parallel to car longitudinal centerline with a tolerance of 0° 10' To adjust rear wheel geometry, move suitably the swinging arm outer support. Slight movements are permitted by the play existing between the support holes A and the mounting screws. Screws B must be tightened to 28.9 to 36.2 Ibft (4000 to 5000 kg mm). Nuts C must be tightened to 43.4 to 50.6 Ib ft (6000 to 7000 kgmm), after adjustment has been carried out. (These directions and specifications are also applicable to 500 Station Wagon).

Wagon' FIG 7:10 Checking left rear wheel toe-in 84 6 Insert the inner spring between the axle shaft and the wheel shaft and couple the spline sleeve to the joint and tighten the screws to a torque wrench setting of 20.3 Ib/ft. 7 Reconnect the parking brake tie rod and adjust the position of the cable using the two stretchers. 8 Refit the wheels and draw up the mounting screws to a torque wrench setting of 32.5 to 39.8 Ib/ft. Carefully lower the vehicle to the floor. 7 :6 Checking and adjusting rear wheel toe-in This check should be carried out by a Fiat agent as special setting equipment is necessary. However, details of this check are given for reference purposes: To check and adjust the rear wheel geometry proceed as follows: 1 Place the vehicle on firmly based stands and remove the front and rear wheels. 2 Install Fiat fixtures A.66062 as shown in FIG 7:12 to enable correct spring compression and wheel location in the vertical position. 3 Lift the rear suspensions by compressing the coil springs and shock absorbers using garage hydraulic jacks. Screw on the fixture lower shank until the index registers with the mark 'Nuova 500' stamped on the bracket. In this position the wheel plane is vertical and the centre O (see FIG 7:6) of wheel shaft results at 5.00 inch from the buffer stop bracket. 4 Secure Fiat support C.696/3 to the wheel drum and connect gauge C.696 to the support. Tighten the two clamping screws as shown in FIG 7:12. 5 Apply at the front of Fiat gauge C.696 bracket numbered C.696/3 as shown in FIG 7:11. 6 Check that the pin mounted on the front end of the bracket C.696/3 is in touch with the front suspension swinging arm pin (see FIG 7:11). If these conditions are not complied with, proceed with item 7. Wheel toe-in angle will vary by 0° 10' under a movement of some 7/32 inch measured at 72.476 inch from wheel centre for Model 500D, and at 76.413 inch from wheel centre for 500 Station Wagon NOTE -- that the toe-in angle Key to Fig 7:9 A Front support B Screw holes for fixing support to underbody C Swinging arm pin nuts

GAUGE C.696 FIG 7:12 Checking left rear wheel toe-in ARM C. 696/3 GAUGE C.696 FIG 7:11 Checking left rear wheel toe-in F500 FIG 7:13 Sectional view of right side rear wheel and axle shaft NOTE—This assembly differs from the early design in the following items: control arm, handbrake shoe actuating lever, flexible joint, axle shaft-to-flexible joint sleeve, sleeve snap ring, axle shaft and joint casing. 85

that the value is the same for both rear wheels. It is important that both rear wheels are set to the same angle otherwise uneven tyre wear and adverse handl- ing conditions will result. When the wheel is parallel to the centre line of the vehicle the pin of bracket C.696/3 will be .216 inch apart from the pin of the front suspension swinging arm. 7 Release the swinging arm outer support to body mounting screws and position arm in such a way as to obtain the condition as described in Number 6 above. After the adjustment has been completed tighten the outer support mounting screws to a torque wrench setting of 28.9 to 36.2 Ib/ft. Also tighten the two swinging arm pin nuts C (see FIG 7:7) to a torque wrench setting of 43.4 to 50.6 Ib/ft. Take off the gauge C.696 with bracket and support C.696/3, and repeat the check and adjustment operations on the other wheel. Care must be taken to ensure that bracket C.696/3 is reversed from the position previously used. New 500 type 500D, 110F and 110L sedan and station wagon: After the rear suspension has been replaced, check and, if necessary adjust the rear wheel geometry. 1 Inflate the tyres to the normal operating pressures. 2 Lower the car body so that the rear wheels are set at 90 deg. to the floor. This condition is obtained when the lowermost portion of the sump is 6.61 inches from the floor level for the new 500D model or the centre rear bracket for jacking up the rear of the vehicle 8.9 inches from the floor level for the 500 Station Wagon. 3 With the vehicle set to the above conditions check the wheel geometry. The wheel plane must converge with the centre line of the vehicle by an angle of 0 deg. 10' (—10', +15') toeing in at the front. 4 The wheel plane must be 22.343 ± .059 inches from the centre line of the vehicle for the 500D model. Whereas for the 500 Station Wagon the distance must be 22.264 ± .059 inches. 5 To adjust the rear wheel toe-in adjust the positions of the mounting screws A and B as shown in FIG 7:7. 86 7:7 Modifications The new 500 Sedan (110F) and late 500 Station Wagon are fitted with modified wheels side flexible joints and rear control arm as shown in FIG 7:13. Together with these modifications a new design rear coil spring has been fitted details of which are given in Technical Data. 7:8 Fault diagnosis (a) Irregular or abnormal tyre wear 1 Incorrect tyre pressure 2 Wheels out of balance 3 Wheels off centre 4 Misadjusted brakes 5 Weak or broken coil springs 6 Excessive load 7 Incorrect wheel alignment (b) Sag on one wheel 1 Incorrect tyre pressure 2 Weak or broken coil spring 3 Wear of shock absorber causing poor dampening action (c) Squeaks, thumps or rattles 1 Wheels out of balance 2 Wheels off centre 3 Misadjusted brakes 4 Weak or broken coil springs or spring seats dislodged 5 Wear of shock absorbers causing poor dampening action 6 Worn rubber bushings in control arms 7 Poor lubrication of wheel bearings (d) Pull to one side 1 Incorrect tyre pressure 2 Misadjusted brakes 3 Distorted suspension arm

8:1 8:2 8:3 8:4 8:5 8:6 Description Front suspension removal and dismantling Leaf spring Swinging arms Kingpin housing Steering knuckle and wheel hub 8:1 Description The independent front suspension assembly fitted to the 'new 500' range comprises a transverse leaf spring which is anchored to the body through two rubber mountings and kingpins through 'estendblocks' as shown in FIG 8:1. The leaf spring also acts as an anti- roll bar which gives normal spring reaction even when the front road wheels encounter a rough road surface. Special polyethylene insulating strips are fitted between the five springs leaves which are all clamped together by two rubber cushioned clamps. Upper movement of the kingpins in the swinging arm is obtained by 'estendblocks'. The half arms are anchored to the body as shown in FIG 8:3 and pivot on their pins through rubber bushes. Double acting hydraulic shock absorbers are fitted to the kingpin housings at the lower end and anchored at the top to the vehicle body. Two rubber buffers are secured to brackets mounted onto the body to limit the spring oscillations. The spring centre bolt is also fitted with a rubber pad. 8:2 Front suspension removal and dismantling To remove the front suspension assembly proceed as follows: F500 87 1 Remove the hub caps and carefully slacken the road wheel retaining bolts. Using a garage hydraulic jack raise the front of the vehicle and place on firmly based stands. Remove the road wheels. 2 Disconnect the steering linkages from the pitman arm, the drag link and the steering knuckle arms. 3 Remove the shock absorber upper mounting nut from the body, lift away the half rubber bush and push down the outer cylinder. 4 Blank off the brake fluid reservoir outlet by inserting a suitable wooden peg through the reservoir filler opening and disconnect the brake hydraulic lines at the wheel cylinders. 5 Fit Fiat crossbeam Arr.2072 under the leaf spring and support this, using a garage hydraulic jack. 6 Remove the self-locking nut securing the leaf spring to the kingpin housing and ease out the spring mounting bolt taking care not to damage the thread. Also remove the nuts securing the swinging arm pin to studs on the body and remove the swinging arm assembly. Carefully lift out the adjusting shims and spacers from the studs making a careful note of the number of the shims and their locations. 7 Remove the nuts securing the leaf spring elastic mounting to the body (see FIG 8:4), and lower the 8:7 8:8 8:9 8:10 8:11 Hydraulic damper Front suspension assembly and installation Steering geometry Modifications Fault diagnosis

FIG 8:1 Front suspension SHOCK ABSORBER SWINGING ARM SWINGING ARM PIN KING PIN LEAF SPRING KING PIN HOUSING FIG 8:2 Right front suspension hydraulic jack slowly so allowing the spring to be lowered from the underside of the vehicle. 8 Using Fiat wrench A.56030, disconnect the hydraulic shock absorber from the kingpin housing. Also remove the swinging arm pin mounting nuts and remove the pin. 9 Using Fiat drift A.66056 or a suitably sized drift remove the 'estenblock' from the kingpin housing. Using a suitably sized punch remove the block pin from the kingpin, remove the lower plug and take off the kingpin. 88 FIG 8:4 Section through one spring mounting Key to Fig 8:3 1 Kingpin housing 2 Estendblock 3 Pin, swinging arm to kingpin housing 4 Half-arm 5 and 6 Nut and splitpin 7 Screw, welded on body 8 Nut, mounting, pin 13 to body 9 Rubber buffer mounting nut 10 Body panel 11 and 12 Camber and castor adjustment shims 13 Pin, swinging arm to body 14 Spacer 15 Cups, for rubber bush 16 Rubber bush FIG 8 :3 Section through left swinging arm Description: The spring comprises a main leaf and four assister leaves. Specially shaped polyethylene insulation strips are fitted between the leaves which are held together by a centre bolt and two elastically mounted side clips as shown in FIG 8 : 1 . The leaf spring is attached to the 8:3 Leaf spring

• When testing the spring never exceed 440.9 lbs load. 4.9212 ± .2362 2.23 ±.10 in/100 lbs in Flexibility, between pos. 2 and pos. 3 Elastic give-in from pos. 2 Camber in lbs Position Load P FRONT LEAF SPRING, LOADED AT CENTER 125 ± 6 mm FREE SPRING 60 mm (2.3622") 137 ± 6 mm (5.3936" ± .2362") FRONT LEAF SPRING, INSTALLED ON CAR Flexibility between pos. 1 and pos. 3 Elastic give-in from pos. 1 Camber Load P Position lbs in 1 Initial load for flexibi- lity check-up . . 220.5 in in/100 lbs 2 Static load . . . . 297.6 1.1023 ±.1181 1.55 ± .07 1.7125±.0984 330.7 Final load for flexibi- lity check-up . . 3 4 Metal-to-metal deflec- tion load . . . . 451.9 Spring specifications are intended at assembly conditions, i. e., with pre-compressed rubber pads and without bumpers. Give-in check-up must be carried out by loading both eyes simultaneously. FIG 8:5 Spring deflection test F500 89

Key to Fig8:6 1 Half-arms 2 Pin, arm to body mounting 3 Pin, arm to kingpin housing mounting 4 and 5 Washer and nut 6 and 8 Cups, rubber bushes 7 Rubber bushes 9 and 10 Sptitpins and nuts, mounting, pin (2) to arms TOOL A.66054 PULLER A.40005/ FIG 8:7 Removal of rubber bushes by universal puller A.40005 and arm retainer tool A.66054 DRIFT ROD A.66056 FIG 8:8 Drift rod A.66056 for kingpin housing Estend- block' removal and installation 90 Inspection: Thoroughly clean the half arms and dry using a com- pressed air jet. Then proceed as follows: 1 Thoroughly inspect the half arms to ensure that they are not distorted or show signs of cracking which, if evident, should be renewed. Compare the two half arms to ensure that they have the same inclination and that the holes are not elongated but are true and properly aligned. kingpin housings by 'estendblocks' which are fitted in the main leaf eyes. A specially shaped rubber buffer is mounted on the spring centre bolt. Leaf spring inspection and repair: To dismantle the leaf spring assembly remove the two side clips and the centre bolt. Thoroughly wash all parts and to inspect proceed as follows: 1 Inspect carefully to check that the leaves are not broken or show signs of cracking which, if evident, the leaf must be renewed. It should be noted that the third spring leaf is not available as a service replace- ment part which means that if this leaf is damaged the whole spring must be renewed. 2 Check that there is no paint or underseal present between the leaves which, if evident, must be removed. 3 Ensure that the mating surfaces of the leaves are perfectly smooth and clean. If there are signs of rusting or slight indentations, these areas must be cleaned using a file. Any deep indentations will be a source of weakness and the leaf must be renewed. 4 The 'estendblocks' are press fitted into the main leaf eyes and must be thoroughly inspected for excessive wear, signs of seizure and dry operation of the rubber parts. The 'estendblocks' should be renewed if there is any doubt as to their condition. To remove and replace the 'estendblocks' use Fiat .drift A.66056 or a suitably sized drift as shown in FIG 8 :8. 5 Check the condition of all rubber pads, the centre buffer and the polyethylene linings for signs of wear, cracking or splits and, if evident, new parts must be fitted. 6 Once the spring has been reassembled it should be tested by loading as shown in FIG 8 :5. 8:4 Swinging arms Description: The swinging arms comprise two pressed steel sheet half arms which are joined by two pins, one on the kingpin housing and the other on the body (see FIG 8:6). Rubber bushes ('flanblocks') are press fitted into the half arms for the attachment of the swinging arm pin to the body as shown in FIG 8 :6. Dismantling: 1 Clamp the swinging arm into a vice and fit Fiat tool A.66054 as shown in FIG 8:7. Remove the splitpin and nut securing the half arms onto their pin. 2 Using a universal two leg puller or Fiat puller A.40005 together with items 1 and 5 pull out the rubber bushes as shown in FIG 8:7. Remove tool A.66054 insert it on the other half arm and repeat the operation performed for the bush removal on the first arm.

the camber and castor adjuster shims does not show any signs of indentation or roughness which could affect the accuracy of adjustment on reassembly. If there are any signs of rust or small markings these should be smoothed out using a file. 3 Inspect the condition of the half arm bushes, the inner surface of which must not show signs of seizure and the clearance of the bush to pin must not be greater than .01 57 inch. Upon initial assembly the fit clearance is .00059 to .0059 inch. Ensure that the rubber parts of the bush are not torn, cracked or show signs of weakness which, if evident, must be renewed. 4 Use Fiat tool A.66058 or a suitably sized drift for refitting the rubber bushes into the swinging arms. Upon reassembly it should be observed that the tightening of the two swinging arms mounting nuts 5 (see FIG 8:3), must be carried out whilst keeping the axis of the swinging arm and the pin hole for the screws 7 on the same plane otherwise distortion can occur. 8:5 Kingpin housing 1 To remove and replace the 'estendblocks' use Fiat tool A.66056 as shown in FIG 8:8. Ensure that the 'estendblocks' is not worn and that there are no signs of seizure on its inner surface, or that the rubber has hardened. Renew if necessary. 2 Check that the kingpin to bush clearance is not greater than .0079 inch. The clearance when fitted new is .00063 to .00213 inch. If the clearance is excessive the two bushes must be renewed and also the kingpin if excessive wear is evident. To remove and refit the kingpin bushes use Fiat tool A.66016 and after reassembly the bushes must be accurately refaced using a reamer set to a diameter of .5912 to .5922 inch. If considered necessary use Fiat Fixture C.1004 to check that the kingpin housing has not been distorted which, if evident, the housing must be renewed. 3 Whilst the kingpin assembly is being inspected ensure that the lubrication hole is free to allow the passage of oil. 4 To prevent incorrect loading of the 'estendblocks' that is press fitted into the kingpin housing, the housing to swinging arm pin nut must be tightened with the parts so arranged that the angle between the swinging arm plane and the housing axis is approximately 95 deg. as shown in FIG 8:14. 8:6 Steering knuckle and wheel hub Dismantling: 1 To remove the wheel hub cap use Fiat puller A.46023 as shown in FIG 8 :9. 2 Using a universal two leg puller or Fiat puller A.40005 together with items 1 and 9 remove the wheel hub/ drum assembly having first extracted the splitpin and released the hub retaining nut (see FIG 8:10). Later models have a staked nut with no splitpin. The nut should be freed with a punch and discarded. 3 Remove the outer roller bearing, the oil seal and the inner roller bearing outer race from the drum and pull out the steering knuckle inner roller bearing inner ring using Fiat puller A.46000 F500 PULLER A.46023 FIG 8:9 Removing right front wheel hub cap by remover A.46023 UNIVERSAL PULLER A. 40005/ FIG 8:10 Removing left front wheel brake drum by puller A.40005 4 Release the two brake to steering knuckle mounting nuts and remove the complete brake housing flange. 5 To remove the steering knuckle from the kingpin housing, remove the 'estendblock' from the kingpin housing using Fiat drift A.66056 or a suitably sized drift as shown in FIG 8 :8. 6 Using a suitably sized punch drive the lockpin from the kingpin, remove the lower plug and slide off the kingpin. The steering knuckle is then disengaged together with the snap ring, two thrust washers and a shoulder ring. Inspection: Thoroughly clean all parts and dry using a compressed air jet and to inspect proceed as follows: 1 Check that the steering knuckle and steering arm show 91

Key to Fig 8:11 1 Threaded shank, floor mounting 2 Rod 3 Cylinder upper blanking threaded ring 4 Seal housing 5 Rod seal 6 Tab spring 7 Spring cup 8 Gasket packing spring 9 Casing gasket 10 Vapour pocket drain and chamber 11 Rod guide bush 12 Vapour pocket drain capillary hole 13 Dust shield 92 14 Casing 15 Working cylinder 16 Vapour pocket drain passage 17 Valve lift limiting disc 18 Fluid passage orifice 19 Valve lift adjustment washer 20 Valve star-shaped spring 21 Inlet valve 22 Piston 23 Compression ring 24 Inlet valve holes in piston 25 Rebound valve holes in piston 26 Rebound valve 27 Valve guide cup 28 Rebound valve spring 29 Piston mounting plug 30 Compensating valve 31 Compensating valve annular passage 32 Compensating-and-compression valve carrier plug 33 Compression valve 34 Compression valve orifices 35 Lower plug 36 Threaded shank, lower mounting FIXTURE FIG 8:12 Leaf spring position under full static loads' on fixture A.66061 or A.74061 no signs of distortion or cracking which, if evident, new parts must be fitted. 2 Check the steering knuckle surfaces, that are in con- tact with the bearing inner races for any signs of scoring or seizure. 3 Inspect the condition of the two upper thrust rings and of the lower packing ring. Parts which show sign of excessive wear must be renewed. Lower packing rings are supplied in service in the thicknesses tabulated below. Once the items have been reassembled no appreciable clearance should be evident between the steering knuckle and the kingpin housing. This adjustment is obtained by installing the lower packing ring of suitable size. 4 Check that the seating on the drums for the roller bearing outer races are smooth as no clearance is allowable between the races and their seatings. Care- fully inspect that the bearing cages and the rollers show no signs of chipping, breakage, or discolouration due to overheating. 5 Carefully inspect the seal which must not be torn and it should locate perfectly both on the drum and the steering knuckles. Reassembly: Reassembly is the reverse procedure to dismantling. Oversizes Under- sizes .002 .004 .006 .008 .010 .012 .0979 .1016 .1036 .1056 .1076 .1095 .100 .102 .104 .106 .108 .110 .002 .004 .0957 .0938 .096 .094 Stand. in. in. .0977 in. .098

Description: The front and rear shock absorbers are of the telescopic double acting type. Their dampening action takes place directly on the suspension without the use of any intermediate linkage. The shock absorber comprises a cylindrical body formed by to coaxial tubes 14 and 15 (see FIG 8:11), the inner tube acting as the working cylinder and the outer one as a casing. The fluid reservoir being located between the two sections. A third outer cylinder 13 shields the rod 2 from any road dirt. On the top the cylinder body is enclosed by a bush 11, oil seals 5 and 9 and a housing 4. The rod 2 slides through the seals 5, the upper end is fixed into the vehicle body floor and its lower end carries the piston 22 on which rebound 26 and inlet valves 21 are arranged. The bottom of the shock absorber is closed by a plug 35 with a threaded shank 36 for the shock absorber to be mounted onto the suspension unit. The cylinder 15 and carrier plug 32 is mounted with a compensation valve 30 and a compression valve 33. The piston is provided with two rows of orifices. The internal row is blanked underneath by the rebound valve which operates downwards. The external row is blanked by the inlet valve which opens upwards. Hydraulic shock absorbers fitted since March 1959 are provided with a vapour pocket bleeder from the cylinder exterior. The bleeder device comprises a capillary hole 12 interconnecting the inner cylinder 15 with the upper chamber 10 and also a passage tube 16 from the upper chamber to the fluid reservoir. Any vapour pockets in the pressure cylinder are excluded past the capillary hole 12 into the chamber 10 from which they flow downwards during shock absorber operation through the passage 16 in a light fluid stream and up to the top of the reservoir with the reservoir fluid. Dismantling and inspection: Normally during service if a shock absorber becomes weak in operation then a new unit should be fitted. Should however, it be necessary for the original unit to be overhauled proceed as follows: 1 Thoroughly clean the outer casing in petrol and blow dry using a compressed air jet. 2 Firmly clamp the lower shank of the shock absorber in a vice and telescope upwards the outer casing and using Fiat wrench A.56024 unscrew the upper threaded ring 3 (see FIG 8:11). 3 Remove the shock absorber from the vice and carefully remove the inner cylinder 15 using a screwdriver inserted in the cylinder bottom chamfer and remove the lower plug 32 which carries the compression and compensation valves. 4 Push the rod into the cylinder 15 and clamp the upper shank in a vice. Unscrew the plug 29, and carefully remove the piston 22 together with the inlet and rebound valves. Withdraw the rod 2 from the cylinder 15 and remove the seal gasket, the housing, and threaded ring. Thoroughly wash all parts in petrol and carefully blow dry using a compressed air jet. The following parts should be inspected as follows. Check that the inlet, rebound and compensation valve discs are not deformed or show signs of cracking. F500 93 Inspect the surfaces of the piston, the seal ring and the compression valve to ensure that they are smooth and hydraulic fluid tight. Check that the rebound and compression valve springs and upper seal gasket springs are not broken or weak. Carefully inspect the two seal gaskets for damage or wear and it is recom- mended that they are renewed upon reassembly. Check that the rod and the cylinders show no sign of deformation and that the air pocket evacuating passage is not blocked. Also check that the capillary hole 12 is not blocked. Any parts which show signs of wear or damage must be renewed. Reassembly: Reassembly of the shock absorber is the reverse procedure to dismantling. Special care must be taken when refilling the shock absorber with Fiat SA1 oil otherwise its operating characteristics will be altered. The hydraulic fluid capacity for the front shock absorbers is .112 imperial quarts. The hydraulic capacity for the rear shock absorbers is .088 imperial quarts. Only Fiat—SA1 oil must be used. To insert the components into the shock absorber body proceed as follows: 1 Mount the piston on the rod, and insert the piston and rod assembly into the cylinder 15 (see FIG 8:11). 2 Push the piston against the bush 11 and then very carefully pour the correct amount of hydraulic fluid up to about j inch from the edge. 3 Press fit the plug 32 and pour the remaining fluid into the casing 14. 4 Insert the cylinder 15 into the casing 14 and tighten the upper threaded ring 3. 8 :8 Front suspension assembly and installation 1 Attach Fiat fixture A.66061 to the springs as shown in FIG 8:12 and load it using the centre screw on the fixture until the index 'Nuova 500' appears below the crossbeam lower edge. It is in this position the spring attains the full static load setting as on the FIG 8:13 Installing right front wheel hub cap by tool A.66059 TOOL A.66059

car. Ensure that the upper elastic supports on the studs projecting from the underside of the vehicle body are correctly located and insert the spring. Fit the two support lower caps with elastic pads and screw onto the stud nuts to a torque wrench setting of 28.9 Ib/ft. 2 Assemble the brake housing flange onto the steering knuckle and tighten the nuts to a torque wrench setting of 14.5 Ib/ft. 3 Assemble the roller bearings and seal into the drum hub. Pack the bearings and fill the recess between the bearings with Fiat MR3 grease or an equivalent, and lightly smear the stub axle. Fit the drum assembly over the stub axle and replace the washer and nut. Note that from vehcle number 043624 the righthand hub has a lefthand thread, the nut being identified by a circular groove on the outside face. On hubs locked with a splitpin, tighten the nut to 21.7 Ib/ft, back it off by approximately 60 deg. (one flat) and fit the splitpin. On the later pattern hub, with no splitpin, fit a new nut and make sure it screws in freely. Tighten it to 14.5 Ib/ft, while rocking the hub four or five times to make sure the bearing is properly seated. Undo the nut completely, then tighten it again to 5.1 Ib/ft. Back it off 30 deg. (half a flat) and lock it by staking the rim into the stub axle spline. Hub end play should be .001 to .0039 inch. 4 Using Fiat tool A.66059 as shown in FIG 8:13, reassemble the cap to the hub. Also reassemble the steering knuckle to the kingpin housing replacing the two upper thrust rings, the snap ring and the lower packing ring whose thickness has already been selected as detailed in Section 8:6 to take up any play between the knuckle and the kingpin housing. Secure the steering knuckle pin with the cotter. 5 Reconnect the swinging arm to the wheel assembly using the special nut and bolt. The nut must be screwed onto the bolt A (see FIG 8:14), by arranging the parts so that the angle between the arm plane and the kingpin housing is approximately 95 deg. as shown in FIG 8:14. Tighten the nut to a torque wrench setting of 39.8 Ib/ft. 94 Key to Fig 8:15 (9° = Kingpin housing castor angle) FIG 8:15 Section through steering knuckle and leaf spring mounting at kingpin

6 Insert the swinging arm pin onto the two studs that are welded to the body sides so as to support the front suspension and wheel assembly. 7 Reconnect the kingpin housing to the spring eye by inserting the bolt and tightening the self-locking nut to a torque wrench setting of 28.9 Ib/ft. It is important that during this operation the spring is always kept in the 'set' position by fixture A.66061 so as to ensure correct assembly and prevent excessive strain on the 'estendblocks'. 8 Slide off the swinging arm and insert the spacers and shims S (see FIG 8:16) onto the studs ensuring that the resulting thickness is the same as was found during dismantling. Reattach the swinging arm. Screw on the nuts securing the pin to the body and tighten to a torque wrench setting of 28.9 Ib/ft. 9 Refit the shock absorber securing it to the kingpin housing and to the body inserting the plain washer between the rubber pad and the toothed washer. 10 Carefully remove Fiat fixture A.66061, connect the steering rods, hydraulic brake pipes and refit wheels. Remove the wooden plug from the brake fluid tank inlet opening. Carefully raise the vehicle using a garage hydraulic jack, remove the axle stands and lower slowly to the ground. 11 When both left- and righthand suspension units have been refitted to the vehicle the front end steering geometry must be checked and adjusted. 8:9 Steering geometry Checking of the front wheel geometry is necessary 95 F500 if either excessive tyre wear or irregular steering per- formance is noticed or if the front suspension assembly has been dismantled for repair. The values for the front end setting under a normal static load normally con- sidered to comprise four passengers should be as follows: Camber angle — 1 deg.± 20' Castor angle — 9 deg.± 1 deg. The camber angle shown in FIG 8:14 and the castor angle shown in FIG 8:16 adjustments are performed by inserting shims S (see FIG 8:16) between the swinging arm pin and the spacers on the studs that are welded to the body at points D and E (see FIG 8:16). Shims .0197 inch thick are supplied in service to enable the castor and camber angles to be adjusted. It is suggested that the castor and camber angles are checked at the local agents as specialised equipment is necessary for completion of these checks. Adjustment of castor angle: Slacken the two nuts securing the swinging arm pin to the body and proceed as follows: 1 If the castor angle requires to be increased (see FIG 8:16) move the shims S from the rear screw E to the front screw D. 2 If the castor angle requires to be reduced (see FIG 8:16) move the shims from the front screw D to the rear screw E. Adjustment of camber angle: Slacken the two nuts securing the swinging arm pin D E A C

1 If the camber angle requires to be increased (see FIG 8:16) add the same number of shims S on both screws D and E. 2 If the camber angle requires to be reduced (see FIG 8:16) remove the same number of shims from both screws D and E. The addition or removal of shims at the two points D and E permits camber adjustment to be made without any disturbing of the castor angle. 8:10 Modifications Checking and adjusting castor and camber angles: When checking the castor and camber angle the static loading should be such that the distance between the semi-elliptic spring mountings G (see FIG 8:16) and the floor level to be approximately 6.81 inches, also a distance between the lowermost portion of the sump and the floor level of approximately 6.14 inch for the Model 500D. For the 500 Station Wagon version the distance between centre rear bracket for jacking-up the vehicle and the floor level should be approximately 8.90 inches. All other front wheel alignment specifications are the same as for the remaining 500 saloon models. 8:11 Fault diagnosis (a) Wheel bounce 1 Tyre casing faulty 2 Uneven tyre pressures 3 Wheels out of balance 4 Semi-elliptic mounting spring worn 5 Weak or seized shock absorber 6 Wheel rim or tyre misaligned (b) Suspension noise 1 Lack of lubrication 2 Noisy or inoperative shock absorbers 3 Worn or loose wheel bearings (c) Pull to one side 1 Low or uneven tyre pressures 2 Incorrect front wheel alignment 3 Suspension arms distorted 4 Inoperative shock absorbers 5 Brakes binding (d) Excessive tyre wear 1 Incorrect tyre rotation during servicing periods 2 Incorrect camber angle 3 Incorrect toe-in 4 Incorrect tyre inflation 5 Excessive play at wheel bearings 6 Wheel wobble 7 Stiff suspension arms 8 Brakes out of adjustment (e) Wheel wobble 1 Uneven tyre pressures 2 Loose or worn wheel bearings 3 Inoperative shock absorbers 4 Loose steering knuckle or kingpin housing 5 Incorrect front wheel alignment 6 Control arm rubber bushings, or kingpin housing and semi-elliptic spring 'estendblock' worn 96

9:5 Relay lever and support 9:6 Steering rods 9:7 Front wheel toe-in 9:8 Fault diagnosis 9:1 Description 9:2 Steering wheel removal and refitting 9:3 Steering box removal and refitting 9:4 Steering box dismantling and reassembly 9:1 Description The steering gear fitted to the new 500 range of vehicles is of the worm screw and sector type with a steering ratio of 1:13. The steering gearbox is located on the front lefthand side of the dash wall on the scuttle as shown in FIG 9 : 1 . The steering gear comprises a pitman arm and relay lever pivoting on a pin supported on the body. A central track rod connects the pitman arm to the relay lever. Two track rods connect the pitman arm and relay lever to the knuckle arms. 9:2 Steering wheel removal and refitting To remove the steering wheel proceed as follows: 1 Disconnect the battery positive terminal clamp and remove the horn control from the steering wheel. 2 Remove the cable from the push button seating and the cable insulation sleeve. 3 Using a suitably sized box spanner or Fiat wrench A.8279 unscrew the steering wheel to shaft nut as shown in FIG 9:2. 4 Using the palm of the hands against the back of the steering wheel rim gently tap the steering wheel forwards so releasing it from the inner shaft. F500 97 5 Reassembly is the reverse procedure to dismantling. Care should be taken to ensure that the front wheels are located in the straight ahead position when the steering wheel is being replaced otherwise the steering wheel spokes will not be correctly positioned. 9:3 Steering box removal and refitting To remove the steering box from the vehicle proceed as follows: 1 From inside the vehicle remove the steering column clamp bolt 6 (see FIG 9:3) after flattening the lock- washer 7. 2 From the underside of the vehicle remove the two tie rod locking nuts from the pitman arm and then using Fiat tool A.46006 or a suitable two leg puller withdraw the pins from the seats. 3 Remove the three nuts holding the steering box to the body panel. Ease out the worm screw from the steering shaft and lift away the steering box. 4 To refit the steering box is the reverse procedure to dismantling. The steering box to body mounting nuts should be tightened to a torque wrench setting of 14 Ib/ft to 18 Ib/ft.

RELAY LEVER SUPPORT INTERMEDIATE TIE ROD! STEERING BOX! LEFT HAND TIE ROD FIG 9 :1 Steering box, idler member and steering linkage arrangement on vehicle FIG 9:2 Securing steering wheel mounting nut Key to Fig 9:2 (Tightening torque: 29 to 36 Ib ft) 9:4 Steering box dismantling and reassembly 1 Remove the steering gear housing cover complete with the adjusting screw and locking nut and drain the oil from the unit. 2 Using Fiat puller A.4005.1.5 or a universal two leg puller remove the pitman arm. 3 Remove the cotter pin from the lower thrust bearing adjusting nut and unscrew this nut. 4 Remove the sealing ring at the sector shaft lower end and using Fiat tool A.8065 loosen the eccentric bush adjuster plate bolt and remove both the bolt and the adjusting plate. Also remove the upper sealing ring. 98 5 Lift out the sector together with the upper thrust washer and shims. 6 Remove the steering worm screw by pulling out from below. The two bearing inner rings will remain on the worm screw whilst the lower bearing outer ring will remain in the housing. 7 Remove the oil seal using Fiat tool A.10110 followed by the worm screw upper bearing outer ring using Fiat tool A.66040 or a suitably sized drift. Inspection: 1 Carefully inspect the sector teeth and the worm screw threads to see that there are no signs of seizure, indentations or scoring. Check that the contact faces indicate that meshing between the two parts is taking place at the centre. 2 Check the clearance between the eccentric bush 5 (see FIG 9:5) and the worm sector 11 which must not exceed .0039 inch. These items have an initial assembly clearance of .00 to .0016 inch. It should be noted that if the eccentric bushing to sector shaft clearance exceeds .0039 inch a new bushing should be installed and its inner face reamed using Fiat reamer U.0360.20. 3 Ensure that the worm screw is not distorted. The permissible out of true is .0019 inch. Adjustment: 1 If the backlash between the worm screw and the sector is excessive it should be adjusted by first dis- connecting the pitman arm and its relevant seal. Remove the screw 7 (see FIG 9:5) fixing the abut- ment plate 6. Rotate the eccentric bush 5 by the adjustment plate and move the sector in towards the worm screw. The adjustment plate should be secured again using the second fixing hole. Should the adjustment plate already be fixed in the second hole remove the plate from the bush and rotate one or more serrations and re-secure.

Key to Fig 9:3 1 Steering wheel and column assembly 2 Nut 3 Toothed washer 4 Plain washer 5 Steering column bracket-to-instrument panel screw 6 Steering column-to-worm screw locking screw 7 Lockplate 8 Plain washer 9 Cover screw 10 Toothed washer 11 Cover 12 Gasket 13 Pin 14Nut 15 Plain washer 16 Worm sector adjusting screw 17 Worm sector and shaft assembly 18 Worm screw 19 Thrust washer 20 Shim 21 Splitpin 22 Lower sleeve, bearing retainer and worm screw adjuster 23 Roller bearing 24 Worm screw bearing upper seal 25 Roller bearing 26 Steering gear housing 27 Oil filling and draining plug 28 Eccentric bushing 29 Upper seal 30 Worm screw-to-sector lash adjusting plate 31 Toothed washer 32 Plate screw 33 Lower seal 34 Pitman arm 35 Self-locking nut Inset: Universally-jointed column fitted from late 1971 99 F500

Key to Fig 9:4 1 Worm screw 2 Seal 3 Roller bearing 4 Worm screw adjuster and bearing retainer 5 Pitman arm 6 Worm sector FIG 9:6 Steering box cutaway 100 FIG 9:5 Section of steering box, through worm sector Key to Fig 9:5 1 Sector adjustment screw 2 Locking nut and plain washer 3 Sector thrust washer 4 Shim 5 Eccentric bush 6 Bush adjusting plate 7 Plate screw and toothed washer 8 Pitman arm 9 Sector lower seal 10 Upper seal 11 Worm sector 12 Worm screw 13 Oil filler and level plug 2 If play is excessive in the worm screw rollers, screw up the lower adjuster ring 4 (see FIG 9:4). Once adjust- ment has been completed the adjuster ring must be secured by the cotter. The ring should be positioned so that the hole in the steering box lines up with one of the spaces between the ring castellations. 3 Should the meshing between the worm screw and the sector not be at the correct central position this condition may be rectified by moving the sector axially. To do this add or remove shims (see FIG 9 :5) below the thrust ring of the worm sector. The final adjustment must be carried out by using the adjust- ment screw 1 (see FIG 9:5) on the cover and then locking the screw by nuts 2. In service shims are supplied .0039 inch thick. The above described adjustments must eliminate any play and back lash in the steering gear without rendering the steering gear stiff to operate between the two locks. 4 During adjustment should any seal be found to be damaged then it should be renewed. Reassembly: Reassembly is the reverse procedure to dismantling but the following points should be noted: 1 All parts should be thoroughly cleaned before

using Fiat W90/M oil (SAE90 EP). 2 The pitman arm nut should be correctly positioned on reassembly to the sector shaft and both are marked with notches or a master tooth on the sector will mate with a double tooth on the pitman arm which will prevent incorrect reassembly. 3 The pitman arm nut must be tightened to a torque wrench setting of 72 Ib/ft. 4 Fill the box up to the level and filler plug with SAE90 EP gear oil. Refitting the steering box: To refit the steering box to the vehicle proceed as follows: 1 Engage the worm screw from the steering shaft by gently manipulating the steering box. 2 Replace the steering box to body nuts and tighten to a torque wrench setting of 14 to 18 Ib/ft. 3 Replace the two track rod pins in their seatings in the pitman arm and tighten the self-locking nuts to a torque wrench setting of 18 to 21 Ib/ft. 4 Replace the steering shaft to worm screw mounting bolt, lock washer and nut. 9 :5 Relay lever and support The steering idler arm is secured to the body by means of a support bracket and a rubber bushed pivot bolt. This is shown in FIG 9:7. When this unit is being serviced the following points should be noted. 1 If there is excessive play between the pin and the bushes the bushes must be renewed. Also check the condition of the pin and if there are signs of excessive wear it must be renewed. 2 To eliminate torsional stresses in the rubber bushes during assembly the pin nut must be tightened to torque wrench setting of 39 to 43 Ib/ft, once the front wheel toe-in has been correctly adjusted with the wheels set in the straight ahead position. 3 The relay lever support to body mounting nuts must be tightened to a torque wrench setting of 14 to 18 Ib/ft. 9 : 6 Steering rods (tie rods) The steering rod is connected to the idler arm and the drop arm by means of non-adjustable ball joints. The track rods are connected to the right and left steering arms by non-adjustable ball joints and comprise two sleeves which are split and having internally threaded ends. The ball joints are clamped to either end of the sleeves. To facilitate adjustment one ball joint end has a lefthand thread and the other a righthand thread. Adjustment is made by loosening both the clamping bolts and turning the central sleeve. To remove the steering rods from the pitman arm, the relay lever and knuckle arms Fiat pullers A.46006 and A.6473 or universal ball joint removers should be used. If excessive play is evident in the ball joint linkage or the pin is damaged the complete ball joint assembly must be renewed. Upon reassembly the tie rod to ball pin knuckle arm nuts must be tightened to a torque wrench setting of 18 to 21 Ib/ft. F500 101 FIG 9:7 Relay lever support section FIG 9:8 Front wheel toe-in checking diagram Key to Fig 9:8 A—B = 000 inch to .079 inch It is important that all steering linkages are thoroughly checked at regular intervals and if any parts are suspect then they must be renewed. 9:7 Front wheel toe-in To check and adjust the front wheel toe-in proceed as follows: 1 Ensure that the tyres are inflated to the recommended pressures. Ensure that the steering wheel is in its

horizontal. Check that the wheels are in the straight- ahead position. 2 Load the vehicle to static load conditions or with four average size passengers. 3 Move the vehicle forwards for a distance of approxi- mately six yards so that the suspension may settle correctly. 4 The toe-in measurements should be taken at the same point of the wheel rim. Measure at A (see FIG 9:8) then back up the car to bring points A to the position B and remeasure. The value obtained at A should be equal to or greater than B within .0079 inch. 5 As previously described the steering rods are adjust- able in length. Loosen the clamps and screw in or out the adjusting sleeves and before tightening the clamp ensure that the sleeve slot registers with the clamp joint. With the clamp fully tightened there should always be a gap between the joint faces. 6 If the steering gear has been re-installed the correct front wheel toe-in must be set. Then the relay lever pin nut must be tightened to a torque wrench setting of 78 to 85 Ib/ft. 9:8 Fault diagnosis (a) Front wheel shimmy 1 Incorrect tyre pressure 2 Incorrect front wheel alignment 3 Loose front wheel bearings 4 Wheels out of balance 5 Loose steering linkage connections 6 Loose steering gear or relay lever support at body mountings 7 Incorrect fitting of steering worm to worm sector (b) Hard steering 1 Incorrect tyre pressure 2 Incorrect front wheel alignment 3 Incorrect adjustment of steering worm to worm sector (c) Hard turning when stationary 1 Incorrect tyre pressure 2 Incorrect adjustment of steering worm to worm sector 102 (d) Pull to one side 1 Incorrect tyre pressure 2 Incorrect front wheel alignment 3 Incorrect front wheel bearing adjustment 4 Distorted kingpin housing or swinging arms 5 Unequal brake adjustment 6 Semi-elliptic spring weak or broken (e) Rattles 1 Loose steering linkage connections 2 Loose steering gear or relay lever support at body mountings 3 Semi-elliptic spring weak or broken 4 Lack of lubrication (f) Loose steering 1 Incorrect front wheel bearing adjustment 2 Loose steering linkage connections 3 Loose steering gear mountings 4 Incorrect adjustment of steering worm to worm sector (g) Jerky steering 1 Incorrect front wheel alignment 2 Incorrect front wheel bearing adjustment 3 Wheels out of balance 4 Loose steering linkage connections 5 Loose or incorrect fitting of worm to sector (h) Side-to-side wander 1 Incorrect tyre pressure 2 Incorrect front wheel alignment 3 Loose steering linkage connections 4 Loose steering gear or relay lever support at body mountings 5 Incorrect fitting of steering worm to worm sector 6 Distorted kingpin housing or swinging arm 7 Semi-elliptic spring weak or broken (i) Tyre squeal on turns 1 Incorrect tyre pressure 2 Incorrect wheel alignment 3 Distorted kingpin housing or swinging arms

10:1 Description 10:2 Maintenance 10:3 Front brakes 10:4 Rear brakes 10:5 Master cylinder 10:6 Wheel cylinder 10:7 Self-adjusting device 10:8 Removing a flexible hose 10:9 Brake fluid reservoir 10:10 Bleeding the system 10:11 Hand parking brake 10:12 Fault diagnosis 10:1 Description All four drum brake units are hydraulically operated by the brake pedal and the handbrake lever operates the rear brakes only through a mechanical linkage which normally requires no separate adjustment (see FIG 10:1). The brake units are of the internal expanding type with one leading and one trailing shoe to each brake. A double ended wheel cylinder expands both shoes into contact with the drum under hydraulic pressure from the master cylinder. When the brake pedal pressure is released the shoes are retracted by means of springs. The brake pedal is directly coupled to the hydraulic master cylinder where pressure on the fluid is generated. This is transmitted to the brakes by a system of metal and flexible pipes. The braking units fitted to the new 500 Sedan models are equipped with a specially designed brake shoe clearance self-adjustment device which eliminates the need for manual adjustment of the brake shoe to drum clearance as is normal practice with a conventional braking system. Every time the brake pedal is depressed the self-adjustment device automatically takes up the excess clearance which may have developed between the lining and the drum due to normal service wear. The brake units fitted to the 500 Station wagon model have a normal brake adjuster which should be used when F500 103 the brake pedal travel becomes excessive. The adjuster is shown in FIG 10:3. On later models a dual circuit system is used. It is described in Section 10:12 10:2 Maintenance Brake adjustment {Station Wagon) Jack each wheel in turn after first chocking the remain- ing three wheels and releasing the handbrake. Depress the brake pedal so as to force the brake shoes against the drum and keeping the shoes in this position turn the adjuster nuts until they contact the shoes and then back the nuts 20 deg. This will correctly set the shoe to drum clearance which should be checked for binding by releasing the brake pedal and ensuring that the road wheel revolves freely. The operation should then be repeated on the other wheels. This adjustment will automatically set the handbrake. Preventative maintenance: 1 Thoroughly inspect the metal hydraulic fluid lines for rusting, cracking or flattening and that they are located away from any sharp edges which could cause a failure.

Key to Fig 10:1 1 Bleeder connections 2 Brake fluid reservoir 3 Service brake pedal 4 Hand lever, mechanical parking brake on rear wheels 5 Hand lever travel adjustment stretchers 6 Stop lamps 7 Mechanical brake operating lever, controlled from lever 4 8 Shoe clearance self-adjusting device 9 Wheel cylinders 10 Master cylinder 11 Stoplight pressure-operated switch FIG 10:2 Left front wheel brake assembly (500 Sedan) SHOE RETURN SPRING SHOE MOUNTING BRACKET SHOE RETAINING PLATE SHOES DEVICE SHOE SELF-ADJUSTING WHEEL CYLINDER SHOE RETURN SPRING 2 Check that the hydraulic flexible hoses are not con- taminated with oil or grease which would destroy the rubber. 3 Ensure that all pipeline fastening clips are secure otherwise hydraulic line failure could occur due to cracking caused by excessive vibration. 104 4 Carefully clean all connections and inspect for hydraulic fluid leaks. Should any leaks be detected then the connections should be tightened taking very great care not to twist the pipes during this operation. 5 Ensure that the hydraulic fluid level in the reservoir is correctly filled up to the top of the filter using Fiat special 'Blue Label' brake fluid. Extra care must be taken to ensure that no fluid is spilled over the body paintwork, as this acts as a strong solvent. 6 Ensure that the play between the brake pedal pushrod and the master cylinder plunger is .019 inch. This will correspond to approximately .098 inch free pedal travel. Never use any fluid but the recommended hydraulic fluid. Do not leave it in unsealed containers as it will absorb moisture which can be dangerous. It is best to discard fluid drained from the system or after a bleeding operation. Observe absolute cleanliness when working on all parts of the hydraulic system. 10:3 Front brakes Front brake drum removal: 1 Remove the wheel trims and carefully slacken the road wheel retaining bolts. Using a garage hydraulic jack raise the front of the vehicle and place on firmly based stands. Remove the road wheels.

remove the wheel grease cap. 3 Using a universal two leg puller or Fiat puller A.40005 together with items 1 and 9 remove the wheel hub/ drum assembly having first extracted the splitpin if fitted and released the hub retaining nut (see FIG 8:10). Dismantling brake unit: 1 Using a compressed air jet thoroughly clean all com- ponents of the brake assembly. 2 Make a note of the location of the shoe return springs and gently ease the shoes away from the brake backplate (see FIG 10:2). 3 Disconnect the hydraulic line from the rear of the wheel cylinder and remove the two cylinder retaining bolts. Lift away the hydraulic cylinder. Brake shoe lining: Check the lining thickness and if found to be exces- sively reduced service replacement shoes must be fitted. The minimum allowable brake lining thickness is .059 inch. Thoroughly check the linings for signs of oil or grease which, if evident, the shoes must be renewed and the drums and oil seals thoroughly inspected for the cause of oil ingress and the cause remedied before reassembly. Do not fit odd brake shoes and do not mix materials or unbalanced braking will result. Do not allow grease, oil or paint to contact the friction linings. Brake drums: Whilst servicing the brakes, thoroughly inspect the drums for scoring, ovality or distortion as well as inspect- ing for minute hair line cracks. The drums may be refaced by using a centre lathe and finally finishing by lapping the drums to smooth out possible tool marks. The maximum permissible oversize beyond the nominal drum diameter of 6.702 to 6.712 inch is .039 inch. This limit must never be exceeded otherwise the strength of the drum will be impaired or a reduction in braking efficiency caused by the increase of shoe expansion travel and the consequent diminished contact pressure. No brake adjustment will be required on the new 500 Saloon models after the drum has been reassembled as the self-adjusting device will accommodate for the shoe position to the new drum diameter during the first operation of the brake pedal. Reassembly of front brakes: This is the reverse procedure to dismantling. Ensure that the pull-off springs are correctly fitted to the holes in the webs of the brake shoes and that the shoes register correctly in the slotted ends of the pistons and the side mounting plate. Upon assembly of the hub and brake drum assembly liberally pack the space between the two bearings with Fiat MR grease, and remount the hub according to the instructions in Chapter 8. F500 FIG 10:3 Section view of left side front brake assembly (500 Station Wagon) Key to Fig 1 0 : 3 1 Wheel cylinder 2 Shoe return spring 3 Adjusting cams 4 Shoe guide pin 5 Shoe with lining 6 Drum 7 Housing flange BRAKE SHOE ADJUSTING DEVICE SHOE WEDGE SELF WHEEL CYLINDER SHOE RETURN SPRING PARKING BRAKE SHOE CONTROL RETURN SPRINGS LEVER SHOE LOCK PLATE BRAKE SHOES SHOE RETURN SPRING SHOE MOUNTING PLATE FIG 10:4 Right rear wheel brake assembly (500 Sedan) 10:4 Rear brakes Rear brake drum removal: 1 Remove the wheel trims and carefully slacken the road wheel retaining bolts. Using a garage hydraulic jack raise the rear of the vehicle and place on firmly based stands. Remove the road wheels. 2 Remove the four drum to hub retaining bolts and spring washers and carefully withdraw the drum from the backplate assembly. Dismantling brake unit: 1 Using a compressed air jet thoroughly clean all components of the brake assembly. 105

(500 Station Wagon) FIG 10:6 Sectional view of a self-adjusting device for automatic brake shoe-to-drum clearance take-up (500 Sedan) Key to Fig 10:6 1 Pin 2 Friction washers 3 Load spring 4 Bushing 5 Shoe 6 Self-adjustment slot 7 Stud 2 Make a note of the location of the shoe return springs and gently ease the shoes away from the backplate (see FIG 10:4) 3 Disconnect the hydraulic line from the rear of the wheel cylinder and also the shoe operating lever return spring, the pin, washer and clevis from the lever so releasing the handbrake inner operating cable. 4 Remove the two cylinder retaining bolts and lift away the hydraulic cylinder. 106 Brake shoe linings: Refer to Section 10:3. Brake drums: Refer to Section 10:3. Reassembly of rear brakes: This is the reverse procedure to dismantling. Ensure that the pull-off springs are correctly fitted to the holes in the webs of the brake shoes and that the shoes register in the slotted ends of the pistons and the side mounting plate. Carefully retract the position of the brake shoes and ease the drum towards the hub ensuring that the four bolt holes line up correctly. Replace the four bolts together with their spring washers, reconnect the hand brake cable. Refit road wheel and wheel trim. 10:5 Master cylinder Operation: Hydraulic fluid is admitted to the master cylinder through hole 8 (see FIG 10:7), it seeps through the gap between the valve carrier ring 17 and the master cylinder dowel and flows through the valve carrier ring holes 15 so reaching the hydraulic lines, therefore filling the system with fluid. When the brake pedal is depressed the plunger is moved forwards by the pushrod 12. This forward action of the plunger 9 and valve carrier 17 brings the valve 16 to rest against the valve front face. The forward movement is continued so causing the valve ring 16 to pass over the compensation hole 5 and cutting off communication with the fluid reservoirs. From this point compression of the hydraulic fluid commences. Hydraulic fluid acting on the front and inner faces of the valve enables perfect valve sealing even under high operation pressures. When the pressure reaches the fluid in the wheel cylinders (see FIG 10:8), it forces the plungers 3 apart and through the plungers stems so operating the brake shoes. After releasing the brake pedal, the combined action of the brake shoe and master cylinder plunger return springs sends the fluid back to the master cylinder and all parts resume their original position. The connection between the hydraulic system and the reservoir is restored. As there are no conventional valves fitted in the master cylinder and the communication orifice between the system and the reservoir is amply dimensioned the bleeding operation is very straightforward. Master cylinder removal: 1 Disconnect the stoplight cables from the pressure operated switch. 2 Using a tapered wood plug of suitable size blank the hole in the brake fluid reservoir. 3 Screw out the four front and rear cylinder brake fluid delivery line connections at the master cylinder. 4 Remove the two master cylinder retaining nuts and spring washers and carefully ease the hydraulic cylinder from the body.

Key to Fig 10:7 1 Plug and spring seat 2 Body 3 Front wheel brake line duct 4 Plunger return spring 5 Compensating hole 6 Plug 7 Supply duct 8 Fluid inlet hole 9 Plunger 10 Plunger snap ring 11 Boot 12 Pushrod 13 Terminal, stoplight switch 14 Rear wheel brake line duct 15 Holes in floating ring carrier for fluid passage 16 Valve 17 Valve carrier 18 Seal FIG 10:8 Wheel cylinder section Key to Fig 10:8 1 Shoe actuating stems 2 Boot 3 Plungers 4 Fluid inlet hole 5 Seal rings 6 and 7 Spring thrust cups and plunger reaction spring Apply the brakes hard for several minutes and inspect the master cylinder and hydraulic connections for leaks. 10:6 Wheel cylinder operation Hydraulic pressure from the master cylinder reaches the fluid in the wheel cylinders by hydraulic pipes and it forces the plungers 3 (see FIG 10:8) apart and through the plungers the brake shoes operate. In the wheel cylinders the sealing rings 5 are axially compressed by the cup 6 under the action of the spring 7. The rings are under the radial and axial action of hydraulic pressure so that their sealing efficiency is increased as the hydraulic pressure increases. Checking wheel cylinders: Once the wheel cylinders have been removed from the brake backplate as previously described remove the rubber boots 2 (see FIG 10:8) on the ends of the cylinder. The plungers, brake shoe stems and sealing rings will be pushed out due to normal spring expansion. Remove the spring thrust cups and plunger reaction spring. 107 F500 Master cylinder reassembly: Ensure that the metal parts are clean. Dry off any solvent used for cleaning. Renew all the rubber seals as a matter of course. Wet the internal parts with clean brake fluid and reassemble them in the order shown in FIG 10:7. Refitting the master cylinder: Carefully locate the master cylinder flange to the body panel ensuring that the pushrod 12 (see FIG 10:7) correctly locates in the plunger 9. Secure the master cylinder flange using the two nuts and spring washers. Refit the hydraulic pipes. Remove the tapered wooden plug from the reservoir and bleed the system as described in Section 10:10. Dismantling master cylinder: 1 Refer to FIG 10 :7 and remove the plunger and rubber boot from the cylinder body. 2 Using a pair of circlip pliers remove the plunger circlip. 3 Carefully slide off from the inside of the cylinder body the plunger, plunger seal, valve ring carrier, valve ring and the reaction spring. 4 Remove the stoplight pressure operated switch. 5 Remove the cylinder body stop plug and upper plug. 6 Carefully inspect the master cylinder inner surface and plunger outer surface to ensure that they have a mirror- like finish and that the play between the two parts is not excessive. Any roughness present on the cylinder inner surface will necessitate renewing the complete assembly. Scoring or corrosion of the surface will quickly damage the rubber seals and can lead to leakage of fluid and consequent partial or complete brake failure. Check that the plunger return spring is not corroded or distorted.