1997 FIAT PUNTO Drum bleed

9«1
Chapter 9
Braking system
Contents
Brake disc - inspection, removal and refitting 4 Brake fluid level check See Weekly checks Brake fluid renewal See Chapter 1A or 1B Brake warning lamp check See Chapter 1A or 1B Front brake caliper - removal, overhaul and refitting 3 Front brake pad check See Chapter 1A or 1B Front brake pads - renewal 2 General information 1 Handbrake - checking and adjustment 9
Handbrake cables - removal and refitting 10 Hydraulic pipes end hoses - renewal 13 Hydraulic system - bleeding 11 Master cylinder - removal and refitting 12 Roar brake shoe check See Chapter 1A or 1B Rear brake shoes - renewal 5 Rear brake drums - removal, inspection and refitting 6 Rear wheel cylinder - removal, overhaul and refitting 7 Stop-light switch - adjustment, removal and refitting 6
Degrees of difficulty

Easy, suitable
far
novice with Sttle
experience ^
Fairly
easy,
suitable ^ (orbeginnerwith ®
some
experience
Fairly difficult, suitable
for
compe«ent ^ CHYmechanlc ^

Difficult, suitable for
experienced DIY « mechanic ^
Very difficult, ^
suitable
for
expert DIY
or professional ^
Specifications
Front disc brakes Type Disc with single-piston sliding calipers Disc diameter Petrol models with single-point Injection 240.0 mm Petrol models with multi-point Injection 257.0 mm Non-turbo diesel models 240.0 mm Turbodieselmodels 257.0 mm Disc thickness (new); Petrol models with single-point injection 10.80 to 11.10 mm Petrol models with multi-point Injection 11.80 to 12.10 mm Non-turbo diesel models 10.80 to 11.10 mm Turbodieselmodels 11.80 to 12.10 mm Minimum disc thickness (wear limit): Petrol models with single-pant Injection 9.20 mm Petrol models with multi-point Injection 10.20 mm Non-turbo diesel models 9.20 mm Turbo diesel models 10.20 mm Maximum disc runout 0.15 mm Brake pad friction material minimum thickness 1.5 mm
Rear drum brakes Drum Inner diameter (new) 180.0 to 180.25 mm Maximum drum diameter (wear limit) 181.35 mm Minimum brake shoe lining thickness 2.0 mm
Torque wrench settings Nm ibf ft
Bfeed
screw 6 4 Brake disc locating studs 12 9 Brake drum locating studs 12 9 Brake pipe and hose unions 14 10 Front caliper mounting bracket-to-hub carrier bolts 53 39 Front caliper-to-caliper bracket guide pin bolts 12 9 fleer wheel cylinder mounting boils 10 7 Roadwheel bolts 85 63

9*8 Braking system
6 Carefully examine the Inside of tho drum. Light scoring of the friction surface is normal, but if heavy scoring Is found, the drum must be renewed. 7 It is usual to find a lip on the dmm's inboard edge which consists of a mixture of rust and brake dust: this should be carefully scraped away, to leave a smooth surface which can be polished with fine (120 to 150-grade) emery paper. If, however, the tip is due to the friction surface being recessed by excessive wear, then the drum must be renewed. 6 If the drum Is thought to be excessively worn, or oval, its internal diameter must be measured at several points using an internal micrometer. Take measurements In pairs, the second at right-angles to the first, and compare the two, to check for signs of ovality. Provided that it does not enlarge the dium to beyond the specified maximum diameter, it may be possible to have the drum refinished by skimming or grinding; if this is not possible, Ihe drums on both sides must be renewed. Note that if the drum is to be skimmed, BOTH drums must be refinished. to maintain a consistent Internal diameter on both sides.
Refitting 9 II a new brake drum is to be Installed, use a suitable solvent to remove any preservative coating thai may have been applied to its internal fnction surfaces. Note that it may also be necessary to shorten the adjuster strut length, by rotating the sedated strut wheel, lo allow Ihe drum lo poss over the brake shoes • see Section S for details. 10 II tho original dfum is being refitted, align the marks made on the drum and hub before removal, then lit the drum over the hub. Refit the locating studs and tighten them to the specified torque. 11 Depress the footbrake repeatedly to expand the brake shoes against the drum, and ensure that normal pedal pressure Is restored. 12 Check and if necessary adjust the handbrake cable as described In Section 9. 13 Refit tho roadwheels, and lower the vehicle to the ground.
7 Rear wheel cylinder -removal, overhaul and refitting jS

A


Warning: Before starting work, refer to the warnings at tho beginning of Sections 2 and 11 concerning the dangers ot handling asbestos dust and hydraulic fluid.
Removal 1 Remove the brake drum fsee Section 6). 2 Remove the brake shoes (see Section 5). 3 To minimise fluid loss during the following operations, remove the master cylinder reservoir cap. then tighten it down onto a piece of polythene, lo obtain an airtight seal.
the hydraulic pipe from the rear of the wheel cylinder 4 Clean the brake backplate around Ihe wheel cylinder mounting boits and the hydraulic pipe union, then unscrew the union nut and disconnect Ihe hydraulic pipe (see illustration). Cover the open ends of the pipe and the master cylinder to prevent dirt ingress, 5 Remove the securing bolts, then withdraw the wheel cylinder from the backplate (soe Illustration).
Overhaul Note: Before commencing woric, ensure that the appropriate wheel cylinder overhaul kit is obtained. 6 Clean tho assembly thoroughly, using only methylated spirit or clean brake fluid, 7 Peel off both rubber dust covers, then use paint or similar to mark one ot the pistons so that the pistons are not interchanged on reassembly. 8 Withdraw both pistons and tho spring. 9 Discard the rubber piston cups and the dust covers. These components should be renewed as a matter of course, and are available 3s part of an overhaul kit, which also Includes the bleed nipple dust cap. 10 Check the condition of the cylinder bore and the pistons - the surfaces must be perfect and free from scratches, scoring and corrosion, It is advisable to renew the complete wheel cylinder if there is any doubt as to the condition ot the cylinder bore or pistons. 11 Ensure thai all components are clean and dry. The pistons, spring and cups should be
8.4 Location of brake tight switch-LHD model shown
withdraw the wheel cylinder from the backplate fitted wet, using hydraulic fluid as a lubricant • soak them in clean fluid before installation. 12 Fit the cups to the pistons, ensuring that they are the correct way round. Use only your fingers (no tools) to manipulate the cups into position. 13 Fit the first piston to the cylinder, taking care not to distort the cup. If the original pistons are being re-used, ihe marks
made on
dismantling should be used to ensure that the pistons are refitted to their original bores, 14 Refit the spring and the second pfston. 15 Apply a smear of rubber grease to Ihe exposed end of each piston and to the dust cover sealing lips, then fit Ihe dust covers to each end of the wheel cylinder.
Refitting 16 Refitting is a reversal of removal, bearirg in mind the following points: a) Tighten the mounting bolts to the specified torque. b) Refit the brake shoes as desenbod
In
Section 5. and refit the brake drum
as
described in Section 6. c) Before refitting the roadwheel
and
lowering the vehicle to the ground, remove the polythene from the fluid reservoir, and bleed the hydraulic
system
as described in Section f
1.
Note that if
nc
other part of the system has been disturbed, it should only bo necessary
to
bleed the relevant rear circuit.
8 Stop-light switch • & adjustment, removal J? and refitting
Adjustment 1 The switch plunger operates on a ratchet 2 If adjustment Is required, pull the plunge fully out - (he 9witch then sell-adjusts as the brake pedal Is applied and released.
Removal 3 Ensure that the ignition Is switched to OfF. 4 For Improved access, remove the driver's side lower facia panel, as described in Chapter 11 (see Illustration). 5 Disconnect the wiring plug from the switch.

Suspension and steering 10*8
9.1 Prise the horn centre pad from the steering wheel hub unbolt the lower end of the damper from the trailing arm. 9 Lower the trailing arm gradually using a trolley jack, until the coil spring Is released from its lower seat on the trailing arm and its upper seat on the subframe. Make a note of the orientation of the coll spring, to aid correct refitting later. Refitting 10 Refitting is a reversal of removal, lighten the damper lower retaining bolt to the specified torque. Trailing arm Note: The rear stub axles are integral with the trailing arm assemblies and cannot be renewed separately. Removal 11 With reference to Chapter 9. carry out the following: a) Remove the brake drum, shoes and adjuster assembly. b) Unbolt the brake hose union from the
rear
of the wheel cylinder. c) Unbolt the brake pipe mounting bracket from the trailing arm. 12 Refer to Section 7 and remove The rear hub and beanng assembly. 13 With reference to the relevant sub-Section, unbolt the lower end of Ihe damper from the trailing arm. 14 Raise the trailing arm using a trolley jack so that the coll spring Is compressed, then slacken and withdraw the trailing arm front mounting bolL 15 With reference to the previous sub-Section, gradually lower the trailing arm using a trolley lack and remove the coll spring. 16 Allow Ihe trailing arm to hang down, then pull the leading edge of the arm down from its mounting bracket. Refitting 17 Refitting Is a reversal of removal. Tighten all suspension fixings to the specified torque settings, but delay this operation until the full weight vehicle is resting on the roadwheeis -this prevents the damper and trailing arm bushes from being strained. 18 On completion, bleed the brake hydraulic system and adjust the operation of the handbrake, with reference to Chapter 9.
9.2 Unplug the wiring from the centre pad at the connector(s)
9 Steering wheel - % removal and refitting ^
Note: This procedure does not apply to vehicles fitted with an airbag A Warning: For safety reasons, owners are strongly advisod to entrust to an authorised Fiat dealer any work which involves disturbing the airbeg system components. The airbag inflation devices contain explosive material and legislation exists to control their handling and storage. In addition, specialised test equipment Is needed to check thet the alrbag system Is fully operational following reassembly.
Removal 1 Ensure that the ignition is switched off, then prise the horn centre pad from the steering wheel hub. Use the blade of a screwdriver, padded with PVC tape to protect the steering wheel (see illustration) 2 Unplug the horn and (where applicable) radio/cassette control switch wiring from the centre pad at the connectors) (see illustration) 3 Turn the steering wheel to its centre position, so that the roadwheeis are pointing straight ahead. 4 Make alignment marks between the steering wheel and the end of the steering column shaft, to aid correct refitting later, 5 Relieve the staking and then slacken and remove tne steenng wheel securing nut (see
9.5 Slacken and remove the steering wheel securing nut Illustration). Discard the nut as a new item must used on refitting. 6 Lift the steering wheel off the column splines. If it is tight, tap il near the centre, usrg the palm of your hand, or twist it from
side to
side, whilst pulling upwards to release il ton the shaft splines. If the wheel is particular tight, a suitable puller should be used.
Refitting 7 Before commencing refitting, lightly eca. Ihe surfaces of the direction indicator cancelling mechanism with grease. 8 Refitting is a reversal of ren>oval.
bearing a
mind the following points: a) Use a new steering wheel
securing not
and tighten it to the specified
torque.
Ensure that its outer collar
Is adequate^
staked to the column shaft
using a
hammer and punch (see Illustrations). b) Ensure that the direction Indicator
swiith
is in the central (cancelled/off)
position,
otherv/ise the sivitch may be damaged X the wheel Is refitted. c) Align the marks made on the
wheel and
Ihe steering column shaft during removeI 9 Note that if necessary, the position of tf* steering wheel on the column shaft cant* | altered in order to centralise the wheel (enstn that the front roadwheeis aro pointing
In the
straight-ahead position), by moving the vMti the required number of splines on the
sfcafc
Fine adjustment can be carried out by adjusting the length of both track-rwa simultaneously, but this operation is best entrusted to a Rat dealer or tyre specialist
9.8a Fit a new steering wheet securing nut... 9.3b ... and stake it to the steering column shaft using o hammer and punch