1967 FIAT 500 drive

4 : 4 Heating system safety device
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
F50057

CHAPTER 5
THE CLUTCH
5:1
5:2
5:3
5:4Description
Removal and installation
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 w i t h d rawal
levers carrier ring and the lever inner tips. The lever outer
tips lift the pressure plate so disengaging the clutch.
F50059
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
5:8Installation of clutch on flywheel
Pilot bushing
Withdrawal mechanism
Fault diagnosis

*Dimension to be obtained by
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 w i t h their relevant nuts and
washers.
4 Replace the carrier ring on the levers and hook up the
retaining springs. 5 :4 Assembly and adjustment
N e w 500 sedan1 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 w i thdrawal 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 t h a n t h e 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 withdrawa l 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 w i t h 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
d i f f i c u l t y in gear selection.

FIG 5:2 Clutch components (new 500, 500D sedan and early station wagon) DRIVEN PLATE
PRESSURE PLATE
LEVER CARRIER LEVER BOLTSBOLT NUTS PRESSURE SPRINGSWITHDRAWAL 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.

FIG 5 . 4 Clutch cover assembly inspection diagram
500F, L and later Station wagon
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
wear7.9 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 w i t h 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 w i t h 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
LEVERBOLT 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 platePILOT A. 62023 FOR
DRIVENPLATE CENTERING

lubricated using Fiat Jota 3 grease.
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 t h a t 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 . 6 2 0 2 3 (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 - 5 0 0 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
F50063
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
ADJUSTABLETIE R O DCLUTCH RELEASE LEVER NUT A N D JAM NUT
FOR TIE R O D CLUTCH RELEASE BOWDEN FIG 5:8 Clutch throw-out mechanism
CLUTCHSHAFT
LEVER-AND-SHAFT
RELEASE
RELEASETHRUST RING
FORK-TO-THRUSTFASTENERS RING
CARBON
RING
WITHDRAWAL FORKCLUTCH

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

CHAPTER 6
GEARBOX AND DIFFERENTIAL UNIT
6:1
6:2
6:3
6:4
6:5
6:6Description
Removal of gearbox/differential unit
Dismantling — gearbox
Reassembly — gearbox
Dismantling — differential and final drive
Reassembly— differential and final drive6:7
6:8
6:9
6:10
6:11
6:12Final 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 t w o parts which split
at the differential centre line. The output drive is trans-
mitted by means of t w o 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.
F50065 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 w i t h 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 t w o pins
which are retained by rings. The primary shaft together
with the first, third and fourth driving gears form a cluster.