1983 FIAT UNO handbrake

0•8Roadside Repairs
To avoid repetition, the procedure for
raising the vehicle, in order to carry out work
under it, is not included before each relevant
operation described in this Manual.
It is to be preferred, and it is certainly
recommended, that the vehicle is positioned
over an inspection pit or raised on a lift. Where
these facilities are not available, use ramps or
jack up the vehicle strictly in accordance with
the following guide. Once the vehicle is raised,
supplement the jack with axle stands.
Jacking
The jack supplied with the car should only
be used to change a wheel. Do not use this
jack when overhaul or repair work is being
carried out; employ a hydraulic or screw jack
and supplement it with axle stands.
Jacking points are located under the sills
for use with the jack supplied.To raise the front end with a garage jack,
locate the jack under the transmission lower
mounting, just below and slightly to the rear of
the transmission oil drain plug. Protect the
mounting by placing a block of wood between
the jack head and the mounting.
To raise the rear of the car, the jack should
be placed under the spare wheel housing as
far to the rear as possible. Place a wooden
bearer between the jack head and the
housing.
Towing
When being towed, use the left-hand front
towing eye.
When towing another vehicle, use the rear
towing eye adjacent to the exhaust tailpipe.
When being towed, remember that the
brake pedal will require heavier pressure due
to lack of servo assistance. Always turn theignition key to MAR to retain the steering in
the unlocked position.
Wheel changing
With the car on firm level ground, apply the
handbrake fully. Remove the hub cap or
wheel trim, if fitted.
Release, but do not remove, the bolts.
Chock the front and rear of the opposite
roadwheel and then raise the car using the sill
jack supplied with the car if it is being done at
the roadside. Alternatively use a workshop
jack supplemented with axle stands.
Remove the wheel bolts, change the wheel
and screw in the bolts finger tight. It is
recommended that the bolt threads are
smeared with multi-purpose grease. Lower
the car, remove the jack and tighten the wheel
bolts to the specified torque. Refit any wheel
trim that was removed.
Spare wheel and jack stowage
Front tow hook Rear tow hook
Jacking, towing and wheel changing

0•10Routine maintenance
Maintenance is essential for ensuring safety and desirable for the
purpose of getting the best in terms of performance and economy
from the car. Over the years the need for periodic lubrication has been
greatly reduced if not totally eliminated. This has unfortunately tended
to lead some owners to think that because no such action is required
the items either no longer exist or will last forever. This is certainly not
the case; it is essential to carry out regular visual examinations as
comprehensively as possible in order to spot any possible defects at
an early stage before they develop into major and expensive repairs.
For information applicable to later models, see Supplement.
Every 250 miles (400 km), weekly,
or before a long journey
m mCheck engine oil level
m mCheck brake reservoir fluid level
m mCheck tyre pressures
m mCheck operation of all lights and horn
m mTop up washer fluid reservoirs, adding a screen
wash, and check operation of washers and wipers
m mCheck coolant level
m mCheck battery electrolyte level
Every 6000 miles (10 000 km)
or six months, whichever comes first
m mRenew engine oil and filter (Chapter 1, Section 2)
m mCheck drivebelt tension (Chapter 2, Section 8)
m mCheck carburettor idle speed and mixture
adjustments (Chapter 3)
m mCheck contact points and dwell angle (mechanical
breaker distributors) (Chapter 4, Section 3)
m mCheck tyre tread wear (Chapter 7, Section 7)
m mCheck disc pads for wear (Chapter 8, Section 3)
Every 36 000 miles (60 000 km)
or three years, whichever comes first
m mRenew the timing belt - 1116 and 1299/1301 cc
(Chapter 1, Section 28)
m mCheck exhaust system for corrosion (Chapter 3,
Section 19)
m mRenew contact breaker points and adjust dwell
angle (mechanical breaker distributors) (Chapter 4,
Section 3)
m mCheck and adjust ignition timing (Chapter 4,
Section 4)
m mRenew spark plugs (Chapter 4, Section 11)
m mCheck clutch adjustment (Chapter 5, Section 2)
m mCheck transmission oil level (Chapter 6, Section 2)
m mCheck driveshaft and steering rack gaiters for splits
(Chapters 7 and 10)
m mCheck rear brake shoe linings for wear (Chapter 8,
Section 4)
m mCheck handbrake travel (Chapter 8, Section 16)
m mCheck headlamp beam alignment (Chapter 9,
Section 17)
m mCheck balljoints for wear (Chapter 10, Section 2)
m mCheck front wheel alignment (Chapter 10, Section 8)
m mCheck suspension bushes for wear (Chapter 11,
Section 2)
m mCheck seat belts for fraying (Chapter 12, Section 23)
m mLubricate controls, hinges and locks
Every 24 000 miles (40 000 km)
or two years, whichever comes first
m mRenew coolant anti-freeze mixture (Chapter 2,
Section 3)
m mRenew transmission oil (Chapter 6, Section 2)
m mRenew brake hydraulic fluid (Chapter 8, Section 12)
m mCheck for underbody corrosion and clean out door
and sill drain holes (Chapter 12, Section 2)
Every 12 000 miles (20 000 km) or
12 months, whichever comes first
m mCheck and adjust valve clearances (Chapter 1,
Sections 5 and 26)
m mRenew air cleaner element (Chapter 3, Section 2)

0•12Routine maintenance
View of front end from below on
55S model
1 Tie-rod end
2 Track control arm
3 Lower mounting
4 Gearchange control rods
5 Exhaust pipe
6 Driveshafts
7 Transmission
8 Sump drain plug
9 Disc caliper
10 Front mounting
11 Horns
12 Radiator
13 Oil filter
View of rear end from below
1 Suspension trailing arm
2 Fuel tank filler hose
3 Rear axle beam
4 Rear silencer
5 Spring seat
6 Expansion box
7 Handbrake cable
8 Fuel tank support strap
9 Fuel tank
10 Handbrake cable adjuster

12The air cleaner on the 1301 cc engine is
mounted on the four flange studs of the
carburettors, their nuts being accessible after
the air cleaner lid has been removed and the
filter element extracted.
13Refitting of all types of air cleaner is a
reversal of removal.
3 Fuel pump-
removal and refitting
2
1On 903 cc engines, the fuel pump is
mounted on the side of the timing chain cover
and is driven by a pushrod from an eccentric
on the front of the camshaft.
2On the 1116 cc and 1301 cc engines, the
fuel pump is mounted on the side of the
crankcase and is driven by a pushrod from an
eccentric on the auxiliary shaft.
3The removal of both types of pump is
carried out in a similar way.
4Disconnect the fuel inlet hose from the
pump and plug the hose (photo).
5Disconnect the fuel outlet hose from the
pump.
6Unscrew the pump fixing bolt and remove it
together with spacer, pushrod and gaskets
(photos).
7Refitting is a reversal of removal. Make sure
that a new gasket is located on each side of
the spacer.
8The gasket on the inboard side of thespacer should always be 0.3 mm thick, but
gaskets for the outboard side are available in
thicknesses 0.3, 0.7 and 1.2 mm, as a means
of adjusting the fuel pump pressure. The
standard fuel pressure is 0.176 bar
(2.55 lbf/in
2). If the pressure is too high a
thicker gasket should be used, if too low, fit a
thinner one.
4 Fuel level transmitter-
removal and refitting
1
1The transmitter is accessible after having
removed the small cover panel from the floor
of the car under the rear seat (tipped forward)
with the floor covering peeled back (photo).
2Disconnect the fuel flow and return hoses
and the electrical leads from the transmitter.
3Unscrew the securing ring and lift the
transmitter from the tank.
4Refitting is a reversal of removal. Use a new
rubber sealing ring.
5 Fuel tank-
removal and refitting
1
1It is preferable to remove the fuel tank when
it has only a very small quantity of fuel in it. Ifthis cannot be arranged, syphon out as much
fuel as possible into a suitable container
which can be sealed.
2The tank is mounted just forward of the rear
axle.
3Disconnect the filler hose and the breather
hose from the tank (photo).
4Unscrew the mounting bolts from the
support straps and lower the tank using a jack
with a block of wood as an insulator. Release
the handbrake cable from its support bracket
on the side of the tank (photo).
5Once the tank has been lowered sufficiently
far, disconnect the fuel supply and return
hoses, breather hose and sender unit leads
and remove the tank from the car.
Warning: Never attempt to
solder or weld a fuel tank
yourself; always leave fuel tank
repairs to the experts. Never
syphon fuel into a container in an
inspection pit. Fuel vapour is heavier than
air and can remain in the pit for a
considerable time.
6If the tank contains sediment or water,
clean it out by using several changes of
paraffin and shaking vigorously. In order to
avoid damage to the sender unit, remove this
before commencing operations.
7Finally allow to drain and rinse out with
clean fuel.
8Refit by reversing the removal operations.
9On 1984 and later models, the fuel tank is
of plastic construction.
Fuel system 3•5
3.6B Fuel pump spacer and pushrod3.6A Fuel pump on mounting studs3.4 Fuel pump
5.4 Fuel tank mounting straps5.3 Fuel tank filler and vent hoses4.1 Fuel tank transmitter
3

8
System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dual-circuit hydraulic with servo unit and pressure regulating valve.
Discs front, drums rear. Handbrake mechanical to rear wheels.
Disc brakes
Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single cylinder, sliding caliper
Disc diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227.0 mm (8.94 in)
Disc thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7 to 10.9 mm (0.42 to 0.43 in)
Minimum regrind thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.0 mm (0.35 in)
Minimum wear thickness of pad friction material . . . . . . . . . . . . . . . . . . 1.5 mm (0.06 in)
Caliper cylinder diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48.0 mm (1.89 in)
Drum brakes
Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single cylinder, with automatic adjusters
Drum internal diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185.24 to 185.53 mm (7.30 to 7.31 in)
Maximum regrind diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187.0 mm (7.37 in)
Minimum shoe lining friction material thickness . . . . . . . . . . . . . . . . . . . 1.5 mm (0.06 in)
Cylinder diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.05 mm (0.75 in)
Master cylinder bore diameter . . . . . . . . . . . . . . . . . . . . . . . . 19.05 mm (0.75 in)
Vacuum servo diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158.5 mm (6.0 in)
Hydraulic fluid type/specification . . . . . . . . . . . . . . . . . . . . . Hydraulic fluid to DOT 3 or 4, or SAE J1703C
System capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.33 litre (0.58 pint)
Torque wrench settingsNm lbf ft
Caliper mounting bracket bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 39
Rear wheel cylinder mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7
Pressure regulating valve mounting bolts . . . . . . . . . . . . . . . . . . . . . . . 20 15
Master cylinder mounting nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 18
Rear brake backplate bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
Chapter 8 Braking system
For modifications, and information applicable to later models, see Supplement at end of manual
Brake disc - inspection, renovation or renewal . . . . . . . . . . . . . . . . . 6
Brake drum - inspection, renovation or renewal . . . . . . . . . . . . . . . . 8
Brake pedal - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Caliper - removal, overhaul and refitting . . . . . . . . . . . . . . . . . . . . . . 5
Disc pads - inspection and renewal . . . . . . . . . . . . . . . . . . . . . . . . . 3
Fault finding - braking system . . . . . . . . . . . . . . . . See end of Chapter
General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Handbrake - adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Handbrake cable - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Hydraulic hoses and pipes - inspection and renewal . . . . . . . . . . . . 11Hydraulic system - bleeding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Master cylinder - removal, overhaul and refitting . . . . . . . . . . . . . . . 9
Pressure regulating valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Rear brake shoes - inspection and removal . . . . . . . . . . . . . . . . . . . 4
Rear wheel cylinder - removal, overhaul and refitting . . . . . . . . . . . . 7
Stop lamp switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Vacuum servo unit - description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Vacuum servo unit - removal and refitting . . . . . . . . . . . . . . . . . . . . 15
Vacuum servo unit - servicing and testing . . . . . . . . . . . . . . . . . . . . 14
8•1
Specifications Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321

3.4 Removing the caliper unit
1 General description
The braking system is of four wheel
hydraulic type with discs on the front wheels
and drums on the rear.The hydraulic system is of dual-circuit type
and incorporates a pressure regulator valve to
limit pressure to the rear brakes during heavy
braking to prevent rear wheel lock up.
A vacuum servo unit is fitted to some
models.
The handbrake is mechanically operated on
the rear wheels.
2 Maintenance
1
1At the weekly service check, inspect the
fluid level in the master cylinder reservoir.
Topping up should only be required at very
infrequent intervals and should only be
necessary owing to the need for extra fluid in
the hydraulic system caused by wear of the
friction material of the disc pads and shoe
linings.
2The need for frequent or regular topping up
will be due to a leak in the system, probably
from a hydraulic cylinder seal or a flexible
hose. Correct the problem immediately.
3Use only clean new fluid for topping up. lt
must be of the specified type and have been
stored in a closed container and not have
been shaken for at least 24 hours (photo).
4At regular intervals, check the hoses and
pipelines for condition. Adjust the handbrake
if the lever travel becomes excessive. Check
the condition and security of the brake servo
vacuum hose. All these operations are
described later in this Chapter.
3 Disc pads-
inspection and renewal
2
1Jack up the front of the car and remove the
roadwheels.
2Extract the spring clips and slide out the
locking blocks (photos).
3On SX versions, carefully disconnect the
wear sensor lead connecting plug.
4Lift the caliper body from the disc and
inspect the thickness of the friction material
on each pad (photo). If it is 1.5 mm (0.06 in) or
less, renew the pads.
5Withdraw the pads and the anti-rattle
springs.
6Brush away any dust and dirt from the
caliper, taking care not to inhale the dust - this
contains asbestos and is thus potentially
injurious to health.
7As the new pads are thicker than the old
ones, the caliper piston must be depressed
8•2 Braking system
3.8A Disc pad and anti-rattle spring
Fig. 8.1 Components of the braking system (LHD shown) (Sec 1)
1 Caliper
2 Hose
3 Master cylinder
4 Fluid reservoir5 Cap and fluid level sensor
6 Vacuum servo unit
7 Rear wheel cylinder8 Pipeline
9 Hose
10 Pressure regulating valve
3.2B Removing a locking block
3.2A Removing a disc pad locking block
clip2.3 Fluid reservoir cap and float for
warning switch

into its cylinder to accommodate them. This
will cause the fluid level to rise in the reservoir.
Anticipate this by syphoning some out
beforehand, but take care not to let it drip
onto the paintwork - it acts as an effective
paint stripperl
8Refit the anti-rattle springs, the pads
(friction lining-to-disc), the cylinder body, the
locking blocks and their retaining clips
(photos).
9Refit the roadwheel and apply the footbrake
hard, several times, to bring the pads into
contact with the brake disc.
10Renew the pads on the opposite brake.
The pads should always be renewed in axle
sets.
11Top up the fluid reservoir.
4 Rear brake shoes-
inspection and renewal
2
1Jack up the rear of the car and remove the
roadwheels.
2Fully release the handbrake.
3Unscrew and remove the drum securing
bolts. One of these is a long locating spigot
for the roadwheel.
4Pull off the drum. lf it is tight, clean off the
rust at its joint with the hub flange, and apply
a little penetrating fluid. Two bolts may be
screwed into the drum securing bolt holes if
necessary and the drum thus eased off the
hub. The securing bolt holes are tapped for
this purpose.
5Brush away all the dust and dirt from the
shoes and operating mechanism, taking care
not to inhale it.
6The friction linings fitted as original
equipment are of the bonded type and the
rivet heads normally used as a guide to wear
are not, of course, fitted. However, if the
thickness of the friction linings is down to
1.5 mm (0.06 in) or less, the shoes must be
renewed. Always purchase new or factory
relined brake shoes.
7Before removing the brake shoes, note the
way in which the shoes are positioned, with
respect to leading and trailing ends (the end
of the shoe not covered by lining material).Note also into which holes in the shoe web
the return springs are connected. Sketch the
shoes or mark the holes on the new shoes
with quick drying paint if you are doubtful
about remembering (photo).
8Undo the steady springs by depressing and
rotating their caps a quarter turn to disengage
the slot from the pin. On later models a
U-shaped steady spring is used. Depress and
slide it out.
9Rotate the hub until the cut-outs in its rear
flange face are in alignment with the shoe
self-adjusters.
10Pivot the trailing shoe on the self-adjuster
post and disengage the ends of the shoe from
the slot in the wheel cylinder tappet and from
the lower anchor block.
11Work the shoe up the self-adjuster pivot
post until the self-adjuster boss enters the
cut-out in the hub flange. The shoe can now
be withdrawn (photo).
12Once off the self-adjuster post, the
pull-off spring tension is eased, as the shoe
can move towards the other, so the springs
can be unhooked.
13Remove the leading shoe in a similar way.
14The new shoes will already be fitted with
new self-adjusters.
15Fit the new shoes to their self-adjuster
posts, making sure that the handbrake shoe
lever is correctly located. Engage the ends of
the shoes.
16Using a wooden or plastic-faced mallet,
tap the shoes inwards against the friction of
their self-adjuster coil springs. This will havethe effect of reducing the overall diameter of
the shoes to facilitate fitting of the shoe return
springs and to allow the brake drum to slide
over them.
17Using pliers, reconnect the upper (longer)
and lower shoe return springs.
18Hold the steady pins in position from the
rear of the backplate. Fit the small coil springs
and the retaining cap, again using pliers to
grip the cap and to depress and turn it to
engage the pin. On later models fit the
U-shaped springs.
19Before refitting the drum, clean it out and
examine it for grooves or scoring (refer to
Section 8).
20Fit the drum and the roadwheel.
21Apply the brakes two or three times to
position the shoes close to the drum.
22Renew the shoes on the opposite brake in
a similar way.
23The handbrake should be automatically
adjusted by the action of the shoe adjuster. If
the handbrake control lever has excessive
travel, refer to Section 16 for separate
adjusting instructions.
5 Caliper- removal,
overhaul and refitting
4
Note: Purchase a repair kit in advance of
overhaul.
1Jack up the front roadwheel and remove it.
2Brush away all dirt from the caliper
Braking system 8•3
4.11 Rear hub showing cut-outs on rear
face for shoe self-adjuster bosses4.7 Rear brake assembly3.8B Cylinder body located on caliper
bracket
Fig. 8.2 Exploded view of caliper (Sec 5)
8

20By connecting a pressurised container to
the master cylinder fluid reservoir, bleeding is
then carried out by simply opening each bleed
screw in turn and allowing the fluid to run out,
rather like turning on a tap, until no air is
visible in the expelled fluid.
21By using this method, the large reserve of
hydraulic fluid provides a safeguard against
air being drawn into the master cylinder
during bleeding which often occurs if the fluid
level in the reservoir is not maintained.
22Pressure bleeding is particularly effective
when bleeding “difficult” systems or when
bleeding the complete system at time of
routine fluid renewal.
All methods
23When bleeding is completed, check and
top up the fluid level in the master cylinder
reservoir.
24Check the feel of the brake pedal. If it
feels at all spongy, air must still be present in
the system and further bleeding is indicated.
Failure to bleed satisfactorily after a
reasonable period of the bleeding operation,
may be due to worn master cylinder seals.
25Discard brake fluid which has been
expelled. lt is almost certain to be
contaminated with moisture, air and dirt
making it unsuitable for further use. Clean
fluid should always be stored in an airtight
container as it absorbs moisture readily
(hygroscopic) which lowers its boiling point
and could affect braking performance under
severe conditions.
13 Vacuum servo unit-
description
A vacuum servo unit is fitted into the brake
hydraulic circuit on 55 and 70 models in series
with the master cylinder, to provide assistance
to the driver when the brake pedal is
depressed. This reduces the effort required by
the driver to operate the brakes under all
braking conditions.
The unit operates by vacuum obtained from
the induction manifold and comprises basically
a booster diaphragm and non-return valve. The
servo unit and hydraulic master cylinder are
connected together so that the servo unit
piston rod acts as the master cylinder pushrod.
The driver’s braking effort is transmitted
through another pushrod to the servo unit
piston and its built-in control system. The servo
unit piston does not fit tightly into the cylinder,
but has a strong diaphragm to keep its edges
in constant contact with the cylinder wall, so
assuring an air tight seal between the two
parts. The forward chamber is held under
vacuum conditions created in the inlet manifold
of the engine and, during periods when the
brake pedal is not in use, the controls open a
passage to the rear chamber so placing it
under vacuum conditions as well. When the
brake pedal is depressed, the vacuum passageto the rear chamber is cut off and the chamber
opened to atmospheric pressure. The
consequent rush of air pushes the servo piston
forward in the vacuum chamber and operates
the main pushrod to the master cylinder.
The controls are designed so that
assistance is given under all conditions and,
when the brakes are not required, vacuum in
the rear chamber is established when the
brake pedal is released. All air from the
atmosphere entering the rear chamber is
passed through a small air filter.
Under normal operating conditions, the
vacuum servo unit is very reliable and does
not require overhaul except at very high
mileages. In this case, it is far better to obtain
a service exchange unit, rather than repair the
original unit.
It is emphasised that the servo unit assists
in reducing the braking effort required at the
foot pedal and in the event of its failure, the
hydraulic braking system is in no way affected
except that the need for higher pressures will
be noticed.
14 Vacuum servo unit-
servicing and testing
1Regularly, check that the vacuum hose
which runs between the servo unit and the
inlet manifold is in good condition and is a
tight fit at both ends.
2If broken or badly clogged, renew the air
filter which is located around the brake pedal
push rod. Access to this is obtained by
disconnecting the pushrod from the
cross-shaft or pedal arm, withdrawing the
pushrod, dust excluding boot and end cap.
3If the new filter is cut diagonally from its
centre hole, future renewal can be carried out
without the need for disconnection of the
pushrod.
4If the efficiency of the servo unit is suspect,
it can be checked out in the following way.
5Run the engine, then switch off the ignition.
Depress the footbrake pedal; the distinctive
in-rush of air into the servo should be clearly
heard. It should be possible to repeat this
operation several times before the vacuum in
the system is exhausted.
6Start the engine and have an assistant
apply the footbrake pedal and hold it down.
Disconnect the vacuuum hose from the servo.
There should not be any in-rush of air into the
servo through the connecting stub. lf there is,
the servo diaphragm is probably faulty. During
this test, expect the engine to idle roughly,
unless the open end of the hose to the inlet
manifold is plugged. Reconnect the hose.
7With the engine off, depress the brake
pedal fully. Start the engine with the brake
pedal still depressed; the pedal should be felt
to go down fractionally.
8If the results of these tests are not
satisfactory, remove the unit and fit a new one
as described in the next Section.
15 Vacuum servo unit-
removal and refitting
3
1Syphon as much fluid as possible out of the
master cylinder reservolr.
2Disconnect electrical leads from the
terminals in the reservoir cap then uncouple
the rigid pipelines from the master cylinder
body. Be prepared to catch leaking fluid and
plug the open ends of the pipelines.
3The master cylinder can be unbolted now
from the servo unit, or detached later when
the complete assembly is withdrawn.
4Working inside the car, disconnect the
servo pushrod from the pedal then remove the
servo mounting nuts.
5Withdraw the servo assembly into the
engine compartment, then remove it to the
bench. lf the master cylinder is still attached,
cover the wings with protective sheeting, in
case brake fluid is spilled during removal.
6Refitting is a reversal of the removal
process, but adjust the pushrod clearance as
described in Section 9. On completion of
refitting, bleed the complete hydraulic system
as described in Section 12. Note: Where the
help of an assistant is available, the servo
pushrod need not be disconnected from the
pedal. The rod is a sliding fit in the servo and
the servo can be simply pulled off the rod.
Refitting without having disconnected the rod
from the pedal can be difficult unless the help
of an assistant is available.
16 Handbrake- adjustment
1
Adjustment is normally automatic, by the
movement of the rear brake shoes on their
automatic adjusters.
However, owing to cable stretch,
supplementary adjustment is occasionally
required at the control lever adjuster nut. The
need for this adjustment is usually indicated
by excessive movement of the control lever
when fully applied.
1The rear brakes should be fully applied
when the handbrake control lever has been
pulled over four or five notches.
2If adjustment is required, release the
8•8 Braking system
16.2 Handbrake adjuster nuts