Front wheel bearing FIAT 500 1970 1.G User Guide

FIG 6:12 Graphic demonstration of C and c
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 o n 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 t w o 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
F50073
bearing outer races w h e n installing into the f i n a l 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 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.

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.

high bearing preload. To reset remove the wheel shaft
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 t h e
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 w i t h
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.
F50083 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 f o r 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).

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

2 Check that the surface of the pin that is in contact with
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 t h a t 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 m o u n t i n g 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 t h a t 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 t w o 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 t w o 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 w i t h 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
F500PULLER
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 t w o 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

to the body and proceed as follows:
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 t w o 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 worn5 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 t y r e 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

normal straight-ahead position with the spokes
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 w i t h 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

2 Using Fiat puller A.46023 as shown in FIG 8 : 9
remove the wheel grease cap.
3 Using a universal t w o leg puller or Fiat puller A.40005
together w i t h 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 t h e
wheel cylinder and remove the t w o 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 w i t h
Fiat MR grease, and remount the hub according to the
instructions in Chapter 8.
F500
FIG 10:3 Section view of left side f r o n t brake assembly
(500 Station Wagon)
Key to Fig 10:3 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 PLATEBRAKE SHOES
SHOE RETURN SPRING
SHOE MOUNTING PLATE
FIG 1 0:4 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 t h e 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.
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