1999 FIAT PUNTO Single point

9*2 Braking system
2.3a Release tho locking clip ...
1 General information
The braking system is of the vacuum servo-assisted. dual-circuit hydraulic type. The arrangement of Ihe hydraulic system is such that each circuit operates one front ond ono rear brake from a tandem master cylinder. Under normal circumstances, both circuits operate In unison However, in the event of hydraulic failure in one circuit, lull braking force will still be available at two diagonally-opposite wheels. All models covered in this manual are fitted with front disc brakes and rear drum brakes. The front disc brakes are aotuated by single-piston sliding lype calipers, which ensure lhat equal pressure is applied to each brake pad. The rear drum brakes incorporate leading and trailing shoes, which are actuated by twin-piston wheel cylinders. A self-adjust mechanism is incorporated, to automatically compensate for brako shoe wear. As the brake shoe linings wear, the footbrnke operation automatically operates the adjuster mechanism, which effectively lengthens the shoe strut and repositions the brake shoes, to remove the llning-to-drum clearance. The mechanical handbrake linkage operates the brake shoos via a lever attached to the trailing brake shoe.
2.3b ... and remove the pad wear indicator wiring and brake fluid line from the suspension strut Load sensitive proportioning valves operate on the rear brake hydraulic circuits, to prevent the possibility of the rear wheels locking before the front wheels under heavy braking. Note: When servicing any part of the system, work carefully and methodically; also observe scmpulous cleanliness when overhauling any part of the hydraulic sysiem. Always renew components (in axle sets, where applicable) if In doubt about their condition, and use only genuine Fiat replacement parts, or at least those of known good quality. Note the warnings given in Safety first and at relevant points in this Chapter concerning fhe dangers of asoestos dust and hydraulic fluid.
Models with anti-lock braking system (ABS) Available as an option on certain models, the anti-lock braking system prevents skidding which not only optimises stopping distances but allows full steering control to be maintained under maximum braking. By electronically monitoring the speed of each roadwheel in relation to the other wneete, Ihe system can detect when a wheel is about to lock-up, before control is actually lost. The brake fluid pressure applied to that wheel's brake caliper is then decreased and restored (or modulated) several times a second until control
£s
regained. The system components comprise an Electronic Control Unit (ECU), four wheel speed sensors, a hydraulic unit, brake lines and dashboard mounted warning lamps.
The hydraulic unit incorporates a tandem master cylinder, a valve block which modulates the pressure in the brake hydrauli: circuits during ABS operation, an accumulator which provides a supply of highly pressursed brake fluid, a hydraulic pump to charge Ihe accumulator and an integral electronic control unit (ECU). The four wheel sensors are mounted on the wheel hubs. The ECU uses the signals produced by the sensors to calculate Ihe rotational speed of each wheel, The ECU has a self-diagnostic capability and will inhibit the operation of the ABS il a fault is detected, lighting the dashboard mounted warning lamp. The braking system will then revert lo conventional. non-ABS operation. II the nature of the laull ie not immediately obvious upon inspection, the vehicle must be taken to a Fiat dealer, who will have the diagnostic equipment
required
lo interrogate the ABS ECU electronically and pin-point the problem
2 Front brake pads - & renewal S

A


Warning: Renew BOTH sets ol front brake pads at the same
time
- NEVER renew the pads on
only
one wheel, as uneven braking may result

A


Warning: Note that the dust created by wear of the pads
may
contain asbestos, which is a health hazard. Never blow It out with compressed air, and don't inhale any of
it.
An approved filtering mask should be worn when working on the brakes. DO NOT use petrol or petroleum-based solvents to clean brake parts; use proprietary braks cleaner or methylated spirit only. 1 Firmly apply the handbrake, then jack up the front of the car and support it securely
on
axle stands (see Jacking and vehicle supporti. Remove the front roadwheeis. 2 Wording on one side of the vehicle, puth the caliper piston into its bore by pulling the caliper outwards. If necessary, press the piston back into its bore using a large G-clamp or a piston retraction tool. Keep a careful eye on the level of brake llufd in Ihe I reservoir as you do this - ensure that the
level
I does not rise above the MAX marking. 3 Whore applicable, release the locking dp and remove the pad wear indicator
wiring end
brake fluid line from the bracket at Ihe
base of
the suspension strut (see illustrations).
Petrol models without ABS 4 Remove the locking clip and exlracl the lower guide pin from the caliper (see illustrations) 5 Pivot the caliper body upwards and support In position with a length of wire or a cabie-fc. Avoid straining the hydraulic hose.
2,4a Remove the locking clip ... 2.4b ... and extract the lower guide pin from the caliper (petrol models without ABS)

Body electrical systems 12*3
3.4 The auxiliary fusebox, located inside the glovebox behind a drop-down panel auxiliary fusebox, which is located inside the glovebox behind a drop-down panel (see Illustration). 5 A blown fuse can be recognised from its melted or broken wire (see illustration). 6 To remove a fuse, first ensure that the relevant circuit is switched off. 7 Using the plastic tool clipped to the main fusebox lid, pull the fuse from its location. 8 Spare fuses are provided in the main fusebox. 9 Before renewing a blown fuse, trace and rectify the cause, and always use a fuse of the correct rating (fuse ratings are specified on the inside of the fusebox cover flap). Never substitute a fuse of a higher rating, or make temporary repairs using wire or metal foil; more serious damage, or even fire, could result. 10 Note that the fuses are colour-coded as follows. Refer to the wiring diagrams for details of the fuse ratings used and the circuits protected. Colour Rating Orange 5A Red 10A Blue 15A Yellow 20A Clear or White 25A Green 30A 11 The radio/cassette player fuse is located In the rear of the unit, and can be accessed after removing the radio/cassette player -refer to Section 12for greater detail.
Relays 12 A relay is an electncally-operated switch, which Is used for the following reasons: 4 A relay can switch a heavy current remotely from the circuit in which the current is flowing, therefore allowing the use of lighter-gauge wiring and switch contacts.
b)
A relay can receive more than one control input, unlike a mechanical switch. c) A relay can have a timer function - for example, the intermittent wiper relay. 13 The main and optional equipment relays are located in the main and auxiliary toseboxes (see Fuses). A number of additional relays may be fitted, depending on model and specification. These are generally mounted
3.5 A blown fuse can be recognised from its melted or broken wire adjacent lo the component being controlled; e.g. the radiator cooling fan relay(s) are mounted on a bracket next the cooling fan itself. 14 The direction Indicator/hazard warning flasher unit is mounted on the underside of the steering column slalk switch unit. It can be accessed by removing the steering column lower shroud panel (see illustration). 15 If a circuit or system controlled by a relay develops a fault, and the relay is suspect, operate the system. If the relay is functioning, it should be possible to hear it click as it is energised, if this is Ihe case, the fault lies with the components or wiring of the system. If the relay is not being energised, then either the relay is not receiving a main supply or a switching voltage, or the relay itself is faulty. Testing is by the substitution of a known good unit, but be careful - while some relays are identical in appearance and in operation, others look similar but perform different functions. 16 To remove a relay, first ensure that the relevant circuit is switched off. The relay can then simply be pulled out from the socket, and pushed back into position.
4 Buibs (exterior lights) -renewal
General 1 Whenever a bulb is renewed, note the following points:
3.14 Removing the direction indlcator/ha2ard warning flasher unit
a) Ensure that the relevant electrical circuit is isolated before removing a bulb. If in doubt, disconnect the battery negative lead before starting work. b) Remember that, if the circuit has just been in use, the bulb may be extremely hot. c) A/ways check the bulb contacts and holder, ensuring that there is clean metal-to-metal contact between the bulb and its live contacts) and earth. Clean off
any
corrosion or dirt before fitting a nevt bulb. d) Wherever bayonet-type bulbs are fitted, ensure that the live contacts) bear firmly against the bulb contact. e) Always ensure that the new bulb is of the correct rating (see Specifications), and that it is completely clean before fitting it; this applies particularly to headlight/foglight bulbs (see following
0 Pay attention to the orientation when fitting multi-filament bulbs (e.g. combined tail/brake light bulbs) • incorrect fitting will cause the filaments to illuminate In the wrong sequence.
Headlight 2 Open the bonnet. Ensure that the headlights are turned off at the stalk switch. Models with single reflector 3 Pull the wiring plug from the rear of the bulb (see illustration). 4 Pull the rubber boot from the rear of the headlight unit (see Illustration).
4.3 Pull the wiring plug from the rear of the bulb 4.4 Pull the rubber boot from the rear of the headlight unit