1983 FIAT UNO brake fluid

4Using a ring spanner and an open-ended
spanner, unscrew and remove the caliper
cylinder housing lower guide bolt (photo).
Release the upper bolt, but do not remove it.
5Swivel the cylinder housing upwards and tie
it up out of the way. There is no need to
disconnect the hydraulic hose. The sensor
wiring plug will have to be disconnected
(where fitted).
6Remove the pads, complete with anti-rattle
springs (photo).
7Clean away all dust and dirt, taking care not
to inhale it as it may be injurious to health.
8The caliper piston must now be fully
depressed to accommodate the new, thicker,
pads. Do this using a G-clamp or lever, but
anticipate a rise in the brake fluid reservoir
level by syphoning out some of the fluid using
a clean syringe.
9Fit the new pads, which must be of the
same type as the originals, complete with
anti-rattle springs.
10Locate the cylinder body. The fixing bolts
are of self-locking type, and should be
renewed whenever they are loosened or
removed. If new ones are not available, clean
the threads of the old ones thoroughly and
apply thread-locking fluid (photo). Tighten the
bolts to the specified torque. Check that the
rubber dust excluders are in good condition.
11Reconnect the sensor wiring plug.
12Renew the pads on the other front wheel.
13Refit the roadwheels, and then apply the
footbrake several times to position the pads
against the discs.14Top up the brake fluid reservoir if
necessary (photo).
Front disc caliper -
removal and refitting#
15Raise the front of the car and remove the
appropriate roadwheel.
16Using a ring spanner and an open-ended
spanner, unscrew and remove the cylinder
housing fixing bolts.
17Withdraw the cylinder housing, and then,
holding it firmly, release the flexible hydraulic
hose union. Unscrew the cylinder body from
the end of the flexible hose, and then cap the
end of the hose to prevent loss of fluid.
18If required, the disc pads can be removed
and the caliper support bracket unbolted and
removed.
19Refitting is a reversal of removal, but use
new fixing bolts.
20Bleed the front hydraulic circuit.
Front disc caliper - overhaul
21The operations are as described in
Chapter 8, Section 5, paragraphs 6 to 13.
Front brake disc - inspection,
renovation or renewal
22The operations are as described in
Chapter 8, Section 6, but the caliper fixing
bolts are secured with thread-locking fluid;
lockplates are not used.
Rear disc pads - renewal ª
23Any wear in the disc pads can be
observed through the aperture in the calipercylinder body, once the car has been jacked
up and the roadwheels removed (photo).
24If the thickness of the pad friction material
is less than 1.5 mm, renew the pads on both
sides in the following way.
25Using a ring spanner and an open-ended
spanner, unscrew the caliper cylinder body
fixing bolts.
26Withdraw the caliper and remove the disc
pads, complete with anti-rattle springs (photo).
27Clean away all dust and dirt, but avoid
inhaling it, as it may be injurious to health.
28Fully retract the caliper piston in order to
accommodate the new, thicker, pads. To do
this, rotate the piston clockwise, using a
suitable tool engaged in the handbrake
sectors (photo). Anticipate a rise in the brake
fluid reservoir level by syphoning out some
fluid, using a clean syringe.
Supplement: Revisions and information on later models 13•101
14B.10 Applying thread-locking fluid to the
bolt threads14B.6 Disc pad and anti-rattle spring
removal14B.4 Unscrewing the caliper cylinder
housing lower guide bolt
14B.28 Rotating a rear caliper piston14B.26 Withdrawing the rear brake caliper14B.23 Rear brake pad inspection aperture
14B.14 Topping up the brake fluid reservoir
(1301 cc Turbo ie model)
13

14B.54 Master cylinder/vacuum servo
located next to the coolant expansion tank
(1301 cc Turbo ie model)
29Fit the new pads, complete with anti-rattle
springs (photo).
30Refit the caliper using new self-locking
bolts, or if not available, apply thread-locking
fluid to clean threads of the original bolts.
Tighten the bolts to the specified torque.
31Apply the brake pedal several times to
bring the disc pads up against the disc.
32Top up the brake fluid reservoir if
necessary.
33Check the adjustment of the handbrake.
34Refit the roadwheels and lower the car to
the ground.
Rear disc caliper -
removal, overhaul and
refitting
¢
35Carry out the operations described in
paragraphs 25 to 27.36Disconnect the handbrake cable from the
caliper. To do this, grip the cable nipple and
pull it until the cable can be slipped out of its
lever groove (photo). If necessary, slacken the
cable adjustment.
37Using a pair of pliers or similar tool, turn
the piston in an anti-clockwise direction until it
can be removed from the cylinder.
38Having obtained a repair kit, renew the
seal and dust excluder.
39Reassemble the piston to the cylinder,
turning it clockwise as far as it will go.
40Reconnect the handbrake cable.
41Carry out the operations described in
paragraphs 30 to 32.
Rear brake disc -
inspection, renovation
or renewal
ª
42The operations are as described in
Chapter 8, Section 6, but the caliper bracket
fixing bolts are of the socket-headed type and
thread-locking fluid is used, not lockplates
(photo).
Pressure regulating valve
43The valve renewal and adjustment
operations are described in Chapter 8,
Section 10, but the luggage compartment
should be loaded with 45 kg and the load
applied to the bracket eye should be 11 kg.
Brake pedal -
removal and refitting#
44The brake master cylinder and vacuum
servo are mounted on the left-hand side of theengine compartment rear bulkhead. In conse-
quence, the brake pedal on right-hand drive
cars operates through a cross-shaft, which is
located underneath the facia panel inside the
car.
45The cross-shaft is supported in two
brackets, whose mounting nuts can be
reached through cut-outs in the insulation on
the engine compartment rear bulkhead (photo).
46To remove the cross-shaft, working inside
the car, take off the cover from the left-hand
end of the shaft, and then disconnect the
servo pushrod from the crankarm on the
cross-shaft (photo).
47Disconnect the brake pedal from the
right-hand crankarm on the cross-shaft
(photo).
48Disconnect the accelerator pedal by
extracting the split pin which secures its pivot
spindle.
49The cross-shaft may now be removed
after extracting the cotter pin from the
left-hand end of the shaft.
50Push the shaft first to the right, and then
to the left, to release it from its brackets.
51Alternatively, the cross-shaft, complete
with brackets, may be removed as an
assembly if the bulkhead nuts are unscrewed.
52Removal of the brake and clutch pedals is
described in Chapter 5, Section 4, but note
that on hydraulic clutch models, the master
cylinder will also require removal as described
in Section 11 of this Chapter.
53Refitting is a reversal of the removal
procedure.
13•102 Supplement: Revisions and information on later models
14B.47 Right-hand end of brake pedal
cross-shaft14B.46 Left-hand end of brake pedal
cross-shaft
14B.45 Brake pedal cross-shaft fixed nut
(arrowed) on engine compartment rear
bulkhead
14B.42 Unscrewing a rear caliper bracket
bolt14B.36 Disconnecting the handbrake cable
from the caliper lever14B.29 Rear disc pad

As it is lifted, invert it and detach the washer
hose from the washer nozzle (photos).
97Where applicable, detach and remove the
washer reservoir from the recess in the front
of the windscreen to allow access to the wiper
motor.
98Unscrew and remove the two wiper motor
retaining screws. Lower and withdraw the
unit, then detach the cover from the motor.
Disconnect the wiring from the wiper motor
and withdraw it from the car (photos).
99Refit in the reverse order of removal.
Check for satisfactory operation of the wiper
and washer on completion.
Windscreen washer reservoir
(Turbo ie models) -
removal and refitting
Á
100Disconnect the battery negative lead.
101Remove the bonnet as described in
Chapter 12.
102Remove the wiper arm and blade as
described in Chapter 9, then unscrew and
remove the pivot nut.
103Undo the air inlet grille retaining screws
noting that two are not fitted with washers.
Where applicable, remove the washer
reservoir filler cap from the reservoir neck
protruding through the grille. Carefully prise
free and lift the air inlet grille clear of the body.
As it is lifted, invert it and detach the washer
hose from the washer nozzle.
104Syphon any remaining washer fluid from
the reservoir, then disconnect it and partiallywithdraw it from the recess in front of the
windscreen so that the wiring connection and
the washer supply hoses (to the windscreen
washer and the rear screen washer nozzles)
can be detached from the pump unit. Remove
the reservoir from the vehicle.
105Refit in the reverse order of removal. If the
washer pump unit was detached from the
reservoir, use a new seal washer when refitting
it. Top up the reservoir and check the screen
washers for satisfactory operation before
refitting the grille panel and the wiper arm/blade.
Tailgate wiper motor
(later models) -
removal and refitting
Á
106Although the tailgate wiper motor differs
in appearance, its removal and refitting
procedures are much the same as those
described for the earlier models in Section 27
of Chapter 9 (photo).
Radio
107All later models are now equipped with
power supply and speaker leads for radio
installation.
108Installation of the standard FIAT aerial
mounted on the windscreen pillar is shown
(photos).
Check control system sensors -
description
109The locations of the sensors referred to in
Chapter 9, Section 34 are given in the
following paragraphs, and their construction
differs according to their individual function.
Brake fluid level sensor
110This is mounted in the master cylinder
fluid reservoir cap, and comprises a pair of
reed switches in a glass bulb, and a magnet at
the end of a float.
111When the fluid level is correct, the
magnetic flux closes the switches. In the
event of a leak in the system, the magnet
moves away, the switches open and the
warning lamp comes on.
Brake disc pad wear sensor
112This is basically a circuit wire embedded
in the pad friction material. As the pad wears,
the wire is eventually exposed and contacts
the disc, whereupon the warning lamp comes
on to indicate that pad renewal is necessary.
Coolant level sensor
113This is located in the cooling system
expansion tank, and is of the reed switch
type, which operates in a similar way to that
described for the brake fluid sensor.
Engine oil level sensor
114This is located at the end of the dipstick,
and comprises a pair of switches at the end of a
bi-metallic strip, heated by electrical resistance.
115The heat is dissipated by the immersion
of the dipstick in the engine oil, so preventing
the bi-metallic strip from curving so much that
the switches would open.
116If the oil level drops, the heat is no longer
dissipated, the switches open, and the
warning lamp comes on.
13•110 Supplement: Revisions and information on later models
15.108B Pillar lower screw for aerial15.108A Pillar upper screws for aerial15.106 Tailgate wiper motor - later model
15.98C . . . and detach the wiring
connector15.98B . . . separate the wiper motor from
its cover . . .15.98A Remove the wiper motor retaining
screws . . .

Door closure sensor
117The sensor consists of a microswitch
within the lock. The switch actuates the
warning lamp according to whether the lock is
in the open or closed mode.
Check control system sensors -
testing
Brake fluid level sensor
118With the fluid level correct, switch on the
ignition and depress the centre of the
reservoir cap. If the sensor switches are
working correctly, then “FAULT” should be
indicated on the check panel.
Coolant level sensor
119With the coolant level in the expansion
tank correct, switch on the ignition and then
pull the wiring plug from the sensor. “FAULT”
should be indicated on the check panel. If it is
not, then it is the panel which is faulty.
120An ohmmeter should be used to check
for continuity, holding the float in both the full
and low level positions.
Engine oil level sensor
121With the oil level correct, disconnect the
wiring plug from the dipstick, and then bridge
the plug terminals (not dipstick side) with a 12
ohm resistor. Switch on the ignition.
122If the red light on the check panel goes
out, then the fault is due to the sensor.
123If the light stays on, then it is the check
panel module which is faulty.
Door closure sensor
124Any fault in the lock microswitch can best
be detected using an ohmmeter.
16 Suspension
Front anti-roll bar -
removal and refittingª
1A front anti-roll bar is fitted to the 1301 cc,
1372 cc ie and 1372 cc Turbo ie engined
models. Removal of the bar on all models isas follows. Firstly loosen off the front
roadwheel bolts, then raise the front of the
car, securely support it on axle stands and
remove the front roadwheels.
2Disconnect the two gearchange rods from
the transmission.
3Unbolt and disconnect the anti-roll bar
insulating clamps from the floorpan (photo).
4Unbolt the end links from the track control
arms and withdraw the anti-roll bar (photo).
5Refitting is a reversal of removal, but only
tighten the nuts and bolts to the specified
torque with the car parked on level ground,
with four passengers and 40 kg of luggage
inside.
Suspension strut - later models
6The suspension strut upper mounting nuts
on later models also secure the brackets for
the mounting of ancillary components such as
the fuel filter, fuel system relays and fuses,
etc. (depending on model).
7When removing the suspension strut units,
it will therefore be necessary to detach and
support these brackets and their fittings
(photo).
17 Bodywork
Plastic components
1With the use of more and more plastic
body components by the vehicle
manufacturers (e.g. bumpers, spoilers, and in
some cases major body panels), rectification
of more serious damage to such items has
become a matter of either entrusting repair
work to a specialist in this field, or renewing
complete components. Repair of such
damage by the DIY owner is not really
feasible owing to the cost of the equipment
and materials required for effecting such
repairs. The basic technique involves making
a groove along the line of the crack in the
plastic using a rotary burr in a power drill. The
damaged part is then welded back togetherby using a hot air gun to heat up and fuse a
plastic filler rod into the groove. Any excess
plastic is then removed and the area rubbed
down to a smooth finish. It is important that a
filler rod of the correct plastic is used, as
body components can be made of a variety
of different types (e.g. polycarbonate, ABS,
polypropylene). Damage of a less serious
nature (abrasions, minor cracks, etc.) can be
repaired by the DIY owner using a two-part
epoxy filler repair material. Once mixed in
equal proportions, this is used in similar
fashion to the bodywork filler used on metal
panels. The filler is usually cured in twenty to
thirty minutes, ready for sanding and
painting.
2If the owner is renewing a complete
component himself, or if he has repaired it
with epoxy filler, he will be left with the
problem of finding a suitable paint for
finishing which is compatible with the type of
plastic used. At one time the use of a
universal paint was not possible owing to the
complex range of plastics encountered in
body component applications. Standard
paints, generally speaking, will not bond to
plastic or rubber satisfactorily. However, it is
now possible to obtain a plastic body parts
finishing kit which consists of a pre-primer
treatment, a primer and coloured top coat.
Full instructions are normally supplied with a
kit, but basically the method of use is to first
apply the pre-primer to the component
concerned and allow it to dry for up to
30 minutes. Then the primer is applied and
left to dry for about an hour before finally
applying the special coloured top coat. The
result is a correctly coloured component
where the paint will flex with the plastic or
rubber, a property that standard paint does
not normally possess.
Rear view mirrors Á
Interior
3The mirror is of safety type, “breaking” off
its ball fixing upon impact from a front seat
occupant.
4To remove the mirror, grip the head and
Supplement: Revisions and information on later models 13•111
16.7 Suspension strut upper mounting
nuts, showing bracket and cable clip on
the 1372 cc ie model16.4 Anti-roll bar fixing nuts (arrowed)16.3 Anti-roll bar clamp
13

Wiring diagrams 14•1
14
Component key for wiring diagrams 1 to 29
Note: Not all the items listed will be fitted to all models
No Description
00200 Alternator with built-in regulator
00500 Battery
01001 Starter motor
01202 Rear front electric window motor
01203 Left front electric window motor
01206 Windscreen wiper motor
01207 Rear screen wiper motor
01252 Right front door locking motor
01253 Left front door locking motor
01254 Right rear door locking motor
01255 Left rear door locking motor
01400 Windscreen washer pump
01401 Rear screen washer pump
01420 Electric fuel pump
01500 Engine cooling fan
01502 Injector cooling fan
01504 Ventilation fan
02001 Engine cut-out solenoid on injection pump
02010 Fuel injector
02011 Fuel injector
02012 Fuel injector
02013 Fuel injector
02015 Supplementary air valve
02210 Accelerator pump outlet cut-out solenoid on
carburettor
02215 Supplementary air valve
02400 Ignition coil
02405 Ignition coil with electronic control unit
02490 Static advance ignition control unit
02492 Microplex ignition system control unit
03000 Insufficient engine oil pressure switch
03002 Right front door ajar switch
03003 Left front door ajar switch
03004 Right rear door ajar switch
03005 Left rear door ajar switch
03006 Handbrake ‘on’ warning switch
03007 Brake stop-lamp switch
03008 Reversing light switch
03028 Radiator thermostatic switch
03029 Coolant overheating warning light thermostatic switch
03034 Injector cooling fan thermostatic switch
03035 Accelerator pump outlet cut-out solenoid thermostatic
switch
03036 Radiator thermostatic switch with two operating ranges
03053 Map reading light switch
03059 Foglamps switch
03060 Rear foglamp switch
03110 Heated rear screen switch
03114 Ventilation fan switch
03123 Air pressure switch
03142 Choke warning light switch
03144 Reset switch
03145 Display switch
03305 Right front door open light push button
03306 Left front door open light push button No Description
03319 Horn push button
03500 Ignition switch
03505 Butterfly valve cut-off switch
03506 Throttle position switch
03530 Right front electric window switch
03531 Left front electric window switch
03546 Rear screen wash/wipe switch
03550 Hazard warning lights switch
04010 Steering column switch unit, direction indicators
04022 Steering column switch unit, headlamps, main beam
and dipped, side lights
04032 Steering column switch unit, windscreen wash/wipe
04214 Fuel injection system control relay
04215 Antiskid system failure relay
04225 Radiator fan 2nd speed engagement relay feed
04241 Foglamps relay feed
04260 Electric windows motor relay feed
04283 Antiskid system relay
04291 Horn relay feed
04292 Heated rear screen relay feed
04441 Dim-dip cut-out 04600 Ignition distributor
04700 Coolant temperature sender unit
04701 Electronic injection coolant temperature sender unit
04720 Oil pressure sender unit
05008 Right headlamp, main beam and dipped with side light
05009 Left headlamp, main beam and dipped with side light
05013 Abnormal fuel consumption sensor
05015 Right foglamp
05016 Left foglamp
05410 Right front direction indicator
05411 Left front direction indicator
05412 Right front side direction indicator
05413 Left front side direction indicator
05640 Rear number plate lamp
05690 Right rear light cluster, sidelight, direction indicator,
brake light, rear foglamp
05691 Left rear light cluster; side light, direction indicator,
brake light, rear foglamp
06000 Centre courtesy light
06026 Map reading light
06076 Ideogram fibre optic light
06080 Heater controls light
06084 Instrument panel light
06300 Sidelights warning light
06305 Main beam headlamps warning light
06310 Rear foglamps warning light
06311 Foglamps warning light
06315 Hazard warning lights warning light
06320 Direction indicators warning light
06335 Insufficient brake fluid level warning light
06336 Handbrake ‘on’ warning light
06343 Insufficient engine oil pressure warning light
06344 Insufficient brake fluid level warning light
06345 Fuel reserve warning light
06350 Coolant overheating warning light

14•2 Wiring diagrams
No Description
06355 Battery charging warning light
06365 Choke warning light
06368 Antiskid system failure lamp
06385 Heated rear screen warning light
06800 Horn
06801 Right horn
06802 Left horn
07000 Coolant level sensor
07001 Engine oil level sensor
07003 Brake fluid level sensor
07015 Right front brake pad wear sensor
07016 Left front brake pad wear sensor
07020 Engine speed sensor
07021 TDC sensor
07022 Anti-knock sensor
07023 Diagnostic socket
07037 Butterfly valve (cut-off) switch
07050 Fuel gauge
07051 Instant fuel consumption gauge (econometer)
07052 Airflow meter
07060 Idle cut-off device
07107 Roadwheel speed sensors
07109 Vacuum switch
07191 Absolute pressure sensor
07192 Vacuum switch
07400 Fuel gauge
07410 Engine oil temperature gauge
07415 Coolant temperature gauge
07420 Engine oil pressure gauge
07430 Tachometer
07460 Clock
07461 Digital clockNo Description
08051 Ignition coil condenser
09000 Dim-dip transformer
09008 Radiator cooling fan 1st speed resistor
09100 Heated rear screen
10022 Cut-off device electronic control unit
10500 Control (fuse) box
10515 Electronic injection control unit
10571 Central locking control unit
10584 Antiskid system ECU
10586 Pressure modulators
59000 Cigar lighter
60000 Instrument panel
60204 Four place fusebox
70090 General earth
70091 General earth
70092 Earth plate
M Electronic control unit
Wire colour codes
A Light blue
B White
C Orange
G Yellow
H Grey
L Blue
M Brown
N Black
R Red
S Pink
V Green
Z Violet
Example of two-colour wire: BN (White/Black) Component key for wiring diagrams 1 to 29 (continued)
Note: Not all the items listed will be fitted to all models

Wiring diagrams 14•3
14
Wiring diagram 1 - starting, ignition, charging, oil pressure, low brake fluid,
choke warning light and handbrake “on” (S and SX models)
Wiring diagram 2 - starting, charging, oil pressure and low brake fluid
(Comfort and ES models)

Wiring diagrams 14•15
14
Wiring diagram 22 - direction indicators, hazard warning lamps, brake stop-
lamps, horn and low brake fluid sensor (1301 cc Turbo ie model)
Wiring diagram 23 - courtesy lamps, heater fan, heater illumination, cigar
lighter, digital clock, radio, low oil pressure lamp, oil pressure switch, oil
temperature gauge and tachometer (1301 cc Turbo ie model)