1970 FIAT 500 bearings

of wear, distorting or unevenness of the surfaces as this
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 t h e 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 J o i n the t w o 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 t h e differential bearing outer races into their
seatings in the bearing housings and also f i t the o i l 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 t w o gears, their relative position is
accurately set during initial assembly at the factory.
F50071 Refer to FIG 6 :8 where it will be seen that t w o 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 = t h e 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 t o p 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 = 7 5 + 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 w i t h 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

TOOL A 62039
TOOLA. 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, t w o 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 f t.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 t w o 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 t w o 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.

although these do not affect the service procedures that
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 case2 Front extension, upper cover and clutch housing nutsloose
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

CHAPTER 7
REAR SUSPENSION AND WHEELS
7:1
7:2
7:3
7:4Description
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 m o u n t e d 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.
F50079 7:5
7:6
7:7
7:8Installation 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 f l u i d 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.

FIG 7 : 1 Rear suspension assembly
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 t w o 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 t w o 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 w it h ou t 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 t h a t the o i l seals f i t 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.

FIG 7 : 3 Fixture A.66064, for swinging arm inspection
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
AB 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 w i t h
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 w i t h 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
KeytoFig7:5 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

A tolerance of —10'.+ 15' is permitted providing
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 w i t h 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 t h e 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 w i t h
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 w i t h 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

FIG 8:14 Swing arm setting
car. Ensure t h a t 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 w i t h 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 w i t h 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 t w o 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