recommended oil FIAT 500 1965 1.G Workshop Manual

Cylinder head installation:
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 t w o 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 t i g h t 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 t w o ends that contact the rocker setscrew and the
F50019
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 t w o 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 t o Fiq
1 :20 FIG 1:20 Valve, pushrod and tappet assembly FIG 1:19 Camshaft. The arrow points to the lube oil
outlet port

After the crankshaft has been reground it is important
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 w i t h .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 i n ,
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
F50025 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 s h o w n in FIG 1 :36.
2
4
6Key t o Fig 1 :36
Rocker shaft
Ducts, cylinder head oil drain
Oil pressure relief valve
to centrifugal filter
9
with central oil gallery
12Sump cooling air conveyor
indicator sending unitOil filler with vent valve
Line, oil delivery to rocker shaft
Level indicator rod 31
5
7Gear pump
8 Oil duct
Centrifugal oil fitter
1110
Crankshaft
Oil pump intake screen filter
13 Low oil pressure FIG 1:36 Engine lubrication diagram

FIG 1:37 Lubrication diagram of engine 120.000
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 o u t t h e 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 w i t h 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 w i t h 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 t w o 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
w i t h 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 : 3 7 ) .
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

5 Using the graduated sector check that all the valve
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 w i t h 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 t h e 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 w i t h 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 w i t h a little grease. Install the outer thrust ring,
F50029 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 w i t h 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 : 4 3 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

sections of the air conveyor securing with seven
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 t w o oil moistened
graphite gaskets. Secure the carburetter using t w o
copper washers and t w o self-locking nuts. Fit the
exhaust silencer and secure to the exhaust manifolds
with nuts and spring washers. Place the t w o 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 w i t h
nuts and toothed washers on the bottom side w i t h
screws and toothed washers.
25 Carefully position the distributor at a 10 deg advance
setting and secure w i t h a
nut, plain washer and
spring washer. Fit the fuel pump to carburetter line
complete w i t h 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 w i t h 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 w i t h its sealing washer.
28 Install the cylinder head cover and oil breather pipe
assembly w i t h a cork gasket inserted between.
Secure w i t h 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
F50031 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 supportFIG 1 :47 Power plant rear suspension FIG 1:46 Cylinder head stud nut tightening sequence.
500 D. F and L Sedan and Station Wagon

FIG 2:18Diagram of blow-by gases re-circulation device
Key to Fig 2:181 Head cover 2 Blow-by gases and oil vapours breather valve 3 Oil filler cap4 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 PipeEngine 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
44For full instruction refer to Section 2 :6. Carburetter cleaning:See Section 2 :6 for full check details. Throttle valve components:
Engine 110 F. 000

indicates the condition inside the combustion chamber
and may be used as a guide to engine tuning.
Before the spark plugs are removed b l o w 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 b r o w n 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 d o w n the threads to clear away any carbon. If a tap is
not available use an old sparking plug with crosscuts d o w nthe 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 w i t h the camshaft gear otherwise it
will be impos-
sible to set the ignition timing.
3:10 Fault diagnosis
(a) Engine w i l l 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

FIG 5:10 Clutch throw-out mechanism
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

3 Check the layshaft and the primary shaft between
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 t h e 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 w i t h 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 w i t h 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 t h e rear bearing onto the shaft. Push the
input shaft forward to enable the clutch shaft coupling
to be inserted in t h e 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 w i t h 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 t w o 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 t h e 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

reassembling and during assembly liberally lubricated
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 w o r m screw f r o m 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 t w o 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 w i t h 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 t w o
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.
F500101
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