parking brake FIAT 500 1959 1.G Workshop Manual

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 7:9 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

CHAPTER 10
THE BRAKING SYSTEM
10:1 Description
10:2 Maintenance
10:3 Front brakes
10:4 Rear brakes
10:5 Master cylinder
10:6 Wheel cylinder10:7 Self-adjusting device
10:8 Removing a flexible hose
10:9 Brake fluid reservoir
10:10 Bleeding the system
10:11 Hand parking brake
10:12 Fault diagnosis
10:1 Description
All four drum brake units are hydraulically operated by
the brake pedal and the handbrake lever operates the rear
brakes only through a mechanical linkage which normally
requires no separate adjustment (see FIG 10:1).
The brake units are of the internal expanding type with
one leading and one trailing shoe to each brake. A double
ended wheel cylinder expands both shoes into contact
with the drum under hydraulic pressure from the master
cylinder. When the brake pedal pressure is released the
shoes are retracted by means of springs.
The brake pedal is directly coupled to the hydraulic
master cylinder where pressure on the fluid is generated.
This is transmitted to the brakes by a system of metal and
flexible pipes.
The braking units fitted to the new 500 Sedan models
are equipped with a specially designed brake shoe
clearance self-adjustment device which eliminates the
need for manual adjustment of the brake shoe to drum
clearance as is normal practice w i t h a conventional
braking system. Every time the brake pedal is depressed
the self-adjustment device automatically takes up the
excess clearance which may have developed between
the lining and the drum due to normal service wear.
The brake units fitted to the 500 Station wagon model
have a normal brake adjuster which should be used when
F500103 the brake pedal travel becomes excessive. The adjuster
is shown in FIG 10:3.
On later models a dual circuit system is used. It is
described in Section 10:12
10:2 Maintenance
Brake adjustment {Station Wagon)
Jack each wheel in turn after first chocking the remain-
ing three wheels and releasing the handbrake. Depress
the brake pedal so as to force the brake shoes against the
drum and keeping the shoes in this position turn the
adjuster nuts until they contact the shoes and then back
the nuts 20 deg. This will correctly set the shoe to drum
clearance which should be checked for binding by
releasing the brake pedal and ensuring that the road wheel
revolves freely. The operation should then be repeated
on the other wheels. This adjustment will automatically
set the handbrake.
Preventative maintenance:
1 Thoroughly inspect the metal hydraulic fluid lines for
rusting, cracking or flattening and that they are
located away from any sharp edges which could cause
a failure.

FIG 10:1 Diagrammatic view of service and rear wheel parking brake system
Key to Fig 10:1 1 Bleeder connections 2 Brake fluid reservoir 3 Service brake pedal 4 Hand lever, mechanical
parking brake on rear wheels 5 Hand lever travel adjustment stretchers 6 Stop lamps 7 Mechanical brake operating lever,
controlled from lever 4 8 Shoe clearance self-adjusting device 9 Wheel cylinders 10 Master cylinder 11 Stoplight
pressure-operated switch
FIG 10:2 Left front wheel brake assembly (500 Sedan)
SHOE
RETURN
SPRINGSHOE MOUNTING
BRACKET SHOE
RETAINING
PLATE SHOES
DEVICESHOE
SELF-ADJUSTING
WHEEL CYLINDERSHOE RETURNSPRING
2 Check that the hydraulic flexible hoses are not con-
taminated with oil or grease which would destroy the
rubber.
3 Ensure that all pipeline fastening clips are secure
otherwise hydraulic line failure could occur due to
cracking caused by excessive vibration.
104
4 Carefully clean all connections and inspect for
hydraulic fluid leaks. Should any leaks be detected
then the connections should be tightened taking very
great care not to twist the pipes during this operation.
5 Ensure that the hydraulic fluid level in the reservoir is
correctly filled up to the top of the filter using Fiat
special 'Blue Label' brake fluid. Extra care must be
taken to ensure that no fluid is spilled over the body
paintwork, as this acts as a strong solvent.
6 Ensure that the play between the brake pedal pushrod
and the master cylinder plunger is .019 inch. This will
correspond to approximately .098 inch free pedal
travel.
Never use any fluid but the recommended hydraulic
fluid. Do not leave it in unsealed containers as it will
absorb moisture which can be dangerous. It is best to
discard fluid drained from the system or after a bleeding
operation. Observe absolute cleanliness when working
on all parts of the hydraulic system.
10:3 Front brakes
Front brake drum removal:
1 Remove the wheel trims 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 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.
105

FIG 10:9 Brake fluid reservoir
Key to Fig 1 0 : 9 1 Reservoir 2 Strainer 3 Cap, vented
PARKING BRAKE CONTROL CABLE AND SHEATH
.CABLE ADJUSTING NUTS
SHOE OPERATING LEVER
LEVER RETURN SPRING
FIG 10:10 Parking brake control and adjusting mech-
anism at lefthand side rear wheel
Inspect the surfaces of the plungers and the cylinder
bore. If there is any roughness, scoring or corrosion the
assembly should be renewed. Check that the reaction
spring and thrust washers are not corroded or distorted,
renewing any defective parts.
Reassembling wheel cylinders:
Clean the metal parts thoroughly and dry off any
solvent used. The rubber parts should be renewed auto-
matically when servicing the cylinder. Wet the internal
parts w i t h clean brake f l u i d and reassemble them in the
order shown in FIG 10 : 8 .
10810:7 Self-adjusting device
The new 500 Sedan is equipped with a specially
designed brake shoe clearance self-adjusting device
which eliminates all need for manual adjustment during
service.
Operation:
On either side face of the brake shoe rim are placed t w o
friction washers in line with an adjustment slot which is
machined into the brake shoe (see FIG 10:6). The
friction washers are held against the shoe by a pin and
bush screw together through the slot with a strong
spring in between. The hollow pin fits onto the stud in the
brake housing flange. A clearance of .0315 inch between
the pin hole and stud permits the necessary movement of
the shoes to ensure proper braking under normal
operating conditions. On later models the self-adjuster
assembly is held together by a circlip.
When the shoe clearance adjustment is no longer
correct, the braking action will overcome the resistance of
the friction washers and drag along the shoes into contact
with the drum. Once the brake pedal has been released,
the action of the return springs will be weaker than the
friction of the adjustment washers on the shoes and so
the shoes will remain in the new position taken up. As
further wear of the linings occurs the shoes will again
automatically be repositioned by the device.
Inspection and assembly:
During normal brake overhaul all the components of
the self-adjusting device should be thoroughly checked
and any parts badly worn or damaged must be renewed.
Before reassembly it is advisable to check the spring
rating using Fiat tester A.11493 by
compressing the
spring to a height of .374 inch which should give a
corresponding load reading of 97 ± 4.9 Ib. To re-
assemble the device after testing proceed as follows:
1 Place the pin of the self-adjusting device on support
A.54002/2 and insert first the friction washer followed
by the shoe, the second friction washer, the load spring
and the bushings.
2 Fit wrench A.54002/1 onto the support and by
exerting a slight pressure to overcome the spring load
fully tighten the bush onto the pin. Lock the pin and
bushing using a centre punch. Alternatively, fit the
circlip.
3 Install the shoes onto the brake housing flange and
hook up the t w o return springs. Move the shoes out-
wards as far as they will go and release them. Check
that during the return of the shoes the friction washers
have stayed in their new position.
10:8 Removing a flexible hose
Never try to release a flexible hose by turning the ends
w i t h a spanner. The correct procedure is as follows:
Unscrew the metal pipeline union nut from its con-
nection with the hose. Hold the adjacent hexagon on the
hose w i t h a spanner and remove the locknut which
secures the hose to the brackets. The hose can now be
turned without twisting the flexible part, by using a
spanner on the hexagon at the other end.
1
2
3

10:9 Brake fluid reservoir
The reservoir is located in the front compartment to the
side of the fuel tank as shown in FIG 10:9. Should it be
necessary to detach the fluid outlet line from the reservoir
the outlet hole must be blanked off using a tapered
wooden peg of suitable length so that the cap may be
replaced to prevent the ingress of foreign matter into
the reservoir and the absorbtion of moisture, oil or petrol
vapours which would alter the properties of the hydraulic
fluid.
A special filter is fitted into the top of the reservoir
through which all fluid used for topping-up the reservoir
must pass to ensure utmost inner cleanliness of the
hydraulic system.
10:10 Bleeding the system
This is not a routine maintenance operation and is only
necessary if air has entered the hydraulic system because
parts have been dismantled or because the f l u i d level in
the reservoir has dropped so low that air has been drawn
into the main feed pipe to the master cylinders.
1 Fill the reservoir w i t h Fiat 'Blue Label' hydraulic fluid.
During the bleeding operation fluid will be used and
constant topping-up of the supply reservoir will be
needed. If this is not done it is possible for air to enter
the master cylinder main feed pipe which will nullify
the operation and necessitate a fresh start.
2 Attach a length of rubber or plastic tubing to the
bleeder screw on the rear wheel cylinder furthermost
from the master cylinder. Immerse the free end of the
tube in a small volume of hydraulic brake fluid in a
clean jar.
3 Open the bleed screw one turn and get a second
operator to press down slowly on the brake pedal. After
a full stroke let the pedal return without assistance,
pause a moment and repeat the d o w n stroke. At first
there will be air bubbles issuing from the bleed tube,
but when fluid alone is ejected, hold the pedal firmly
down on the floor panel and tighten the bleed screw.
Repeat this operation on the other rear brake and then
repeat the operation on the two front brakes.
4 On completion, top-up the fluid in the reservoir to the
correct level. Discard all dirty fluid. If fluid is perfectly
clean, let it stand for twenty four hours to become
clear of air bubbles before using it again.
10:11 Hand parking brake
Normally with the new 500 Sedan model automatic
brake adjusting device, adjustment of the rear brakes
will take up excessive handbrake travel.
If there is excessive travel on the handbrake of the
Sedan model at any time, or in the case of Station Wagon
model even after the rear brakes have been manually
adjusted, suspect worn brake shoe linings or stretched
handbrake cables. Examine the linings and fit replace-
ment shoes if necessary. Check the action of the hand
parking brake again and if there is still too much travel
before the brakes are applied it is permissible to take up as
follows:
1 It is essential to ensure that the rear shoes are correctly
adjusted as described in Section 10:2.
2 Apply the hand parking brake lever until the pawl
engages with the ratchet at the second notch.
F500
FIG 10:11 An exploded view showing the components of
the tandem master cylinder
3 Jack up the rear of t h e vehicle and place on firmly
based stands.
4 Locate the cable adjusting nuts as shown in FIG
10:10 and adjust these until it is just possible to turn
the road wheels by heavy hand pressure. It is important
that both wheels offer the same resistance to turning
to obtain correctly balanced braking.
5 Return the lever to the OFF position and check that
both wheels are quite free to rotate. If a brake tends to
bind, remove the wheel and brake drum and check
the brake shoe pull-off spring is correctly fitted and
that the lever return spring and operating lever are
functioning correctly. Also check for suspected
seizure of the wheel cylinder. When the fault has
been rectified refit the drum. Readjust and recheck.
Removing the hand parking brake cable:
1 Chock the front wheels and release the handbrake.
Raise t h e rear of the vehicle and place on firmly based
stands.
2 Disconnect the cables from the operating levers on
each rear brake unit. Release each cable from its body
mounted bracket.
3 Inside the car, remove the rear seat and the seat belt
fitting from the floor. As necessary, remove the centre
console and the carpet to give access to the cover plate
on the centre tunnel and remove it.
4 Remove the handbrake lever assembly, detach the
cable compensator and pull the cables through the
holes in the box panel.
5 Reassembly is the reverse procedure to removal.
Ensure t h a t the cable is well lubricated and finally
readjust as previously described.
10:12 The dual circuit braking system
This is used on later model cars. A tandem master
cylinder provides t w o entirely separate hydraulic circuits,
one for the front and one for the rear brakes. The
components of the master cylinder are shown in the
exploded view of FIG 1 0 : 1 1 . The principle of operation is
quite straightforward and easy to understand.
169