brake FIAT 500 1971 1.G Workshop Manual

2:12 Fault diagnosis
(a) Leakage or insufficient fuel delivered
1 Air vent in tank restricted
2 Petrol pipes blocked
3 Air leaks at pipe connections
4 Pump or carburetter filters blocked
5 Pump gaskets faulty
6 Pump diaphragm defective
7 Pump valves sticking or seating badly
8 Fuel vapourizing in pipelines due to heat
(b) Excessive fuel consumption
1 Carburetter needs adjusting
2 Fuel leakage
3 Sticking controls or choke device
4 Dirty air cleaner
5 Excessive engine temperature
6 Brakes binding
7 Tyres under-inflated
8 Idling speed too high
9 Car overloaded(c) Idling speed too high
1 Rich fuel mixture
2 Carburetter controls sticking
3 Slow-running screws incorrectly adjusted
4 Worn carburetter butterfly valve
(d) Noisy fuel pump
1 Loose mountings
2 Air leaks on suction side and at diaphragm
3 Obstruction in fuel pipe
4 Clogged pump filter
(e) No fuel delivery
1 Float needle stuck
2 Vent in tank blocked
3 Pipeline obstructed
4 Pump diaphragm stiff or damaged
5 Inlet valve in pump stuck open
6 Bad air leak on suction side of pump
46

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 :2 Right rear suspension assembly, sectioned through brake drum and arm mountings
5 Check the mating surface of the bearing inner rings on
the wheel shaft and ensure that it is perfectly smooth.
Also check that the shaft splines to flexible joint
splines are not distorted or show signs of excess wear.
The maximum permissible wear backlash is .0059 inch.
6 Ensure that the f l e xible joint is not damaged where the
rubber is bonded to the metal. If signs of strain are
indicated a new joint must be fitted.
F50081
Reassembly:
Reassembly of the swinging arm unit is the reverse
procedure to dismantling. The following points should
be noted:
1 Always use Fiat tool A.66056 to install 'estendblock'
on the swing arm.
2 The mounting nuts for the bearing housing to the
brake housing flange should always be tightened to a

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).

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

TOOL A.66062
SUPPORT C. 696/3GAUGE C.696
FIG 7:12 Checking left rear wheel toe-in
ARM C. 696/3
GAUGE C . 6 9 6
FIG 7:11 Checking left rear wheel toe-in
F500
FIG 7:13 Sectional view of right side rear wheel and axle shaft
NOTE—This assembly differs from the early design in the following items: control arm, handbrake shoe actuating lever,
flexible joint, axle shaft-to-flexible joint sleeve, sleeve snap ring, axle shaft and joint casing.
85

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

CHAPTER 8
FRONT SUSPENSION AND HUBS
8:1
8:2
8:3
8:4
8:5
8:6Description
Front suspension removal and dismantling
Leaf spring
Swinging arms
Kingpin housing
Steering knuckle and wheel hub
8:1 Description
The independent front suspension assembly fitted to
the 'new 500' range comprises a transverse leaf spring
which is anchored to the body through two rubber
mountings and kingpins through 'estendblocks' as
shown in FIG 8:1. The leaf spring also acts as an anti-
roll bar which gives normal spring reaction even when the
front road wheels encounter a rough road surface.
Special polyethylene insulating strips are fitted
between the five springs leaves which are all clamped
together by t w o rubber cushioned clamps.
Upper movement of the kingpins in the swinging arm
is obtained by 'estendblocks'. The half arms are anchored
to the body as shown in FIG 8 : 3 and pivot on their pins
through rubber bushes. Double acting hydraulic shock
absorbers are fitted to the kingpin housings at the lower
end and anchored at the top to the vehicle body. Two
rubber buffers are secured to brackets mounted onto the
body to limit the spring oscillations. The spring centre
bolt is also fitted with a rubber pad.
8 : 2 Front suspension removal and
dismantling
To remove the front suspension assembly proceed as
follows:
F50087
1 Remove the hub caps and carefully slacken the road
wheel retaining bolts. Using a garage hydraulic jack
raise the front of the vehicle and place on firmly
based stands. Remove the road wheels.
2 Disconnect the steering linkages from the pitman arm,
the drag link and the steering knuckle arms.
3 Remove the shock absorber upper mounting nut from
the body, lift away the half rubber bush and push d o w n
the outer cylinder.
4 Blank off the brake fluid reservoir outlet by inserting
a suitable wooden peg through the reservoir filler
opening and disconnect the brake hydraulic lines at
the wheel cylinders.
5 Fit Fiat crossbeam Arr.2072 under the leaf spring
and support this, using a garage hydraulic jack.
6 Remove the self-locking nut securing the leaf spring
to the kingpin housing and ease o u t the spring
mounting bolt taking care not to damage the thread.
Also remove the nuts securing the swinging arm pin
to studs on the body and remove the swinging arm
assembly. Carefully lift out the adjusting shims and
spacers from the studs making a careful note of the
number of the shims and their locations.
7 Remove the nuts securing the leaf spring elastic
mounting to the body (see FIG 8 : 4) , and lower the 8:7
8:8
8:9
8:10
8:11Hydraulic damper
Front suspension assembly and
installation
Steering geometry
Modifications
Fault diagnosis

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