Clutch 6*3
6 WorWng inside the vehicle, extract the split pin and remove the washer securing the master cylinder pushrod to the clutch pedal. Dsoonnect the pushrod from the pivot. 7 Have an assistant support the master cylinder In the engine compartment, then unscrew the mounting bolts. Withdraw the master cylinder from the engine compartment, 8 II is not possible to obtain an overhaul kit from Flat however some motor factors may be abls to supply one. Follow the Instructions with the repair kit if obtained.
Refitting 9 Refit the clutch master cylinder by following ihe removal procedure In reverse, noting the following. a) Apply a
Utile
high-melting point grease to the clutch pedal pivot. b) Tighten the mounting bolts and union nut securely. cj Fit a new split pin to the pushrod. d) Where removed, refit the alternator
as
described In Chapter 5A e) On completion bleed the clutch hydraulic system as descnbed in Section
A.
7 Clutch assembly -
removal,
inspection
and
refitting
S Clutch slave cylinder-removal and refitting
Note: This procedure applies to models fitted
ivrth
the hydraulically-operated clutch release mechanism. Note: Refer to the warning at the beginning
of
Section A regarding the hazards of working
with
hydraulic fluid.
Removal 1 Remove the battery and battery tray as described in Chapter 5A. 2 Fit a brake hose clamp to tha hose leading to the clutch slave cylinder. 3 Unscrew the union nut and disconnect the hydraulic pipe from the slave cylinder. Be prepared for some fluid loss by placing rags beneath the cylinder. 4 Unscrew the mounting bolts and release the slave cylinder pushrod from the release am on the transmission, then remove the unit from the engine compartment (see Illustration). 5 It is not possible to obtain an overhaul kit from Flat however some motor factors may be able to supply one. Follow tha instructions with the repair kit if obtained.
Refitting 6 Refit the clutch slave cylinder by following the removal procedure In reverse, noting the following. a) Apply a little high-melting point grease to the tip of the slave cylinder pushrod. b) Tighten the mounting bolts and union nut securely. c) On completion bleed the dutch hydraulic system as described in Section A.
A
Warning: Dust created by clutch wear and deposited on the clutch components may contain asbestos, which Is a health hazard. DO NOT blow it out with compressed air, or inhale any of it. DO NOT use petrol or petroleum-based solvents to clean off the dust. Brake system cleaner or methylated spirit should be used to flush the dust Into a suitable receptacle. After the clutch components are wiped clean with rags, dispose of the confam/nafed rags and cleaner In a sealed, marked container. Note: Although some friction materials may no longer contain asbestos, it is safest to assume that they DO. and to take precautions accordingly.
Removal 1 Unless the complete engine/transmission is to be removed from the car and separated for major overhaul (see Chapter 2D), Ihe clutch can be reached by removing the transmission as descnbed in Chapter 7A, 2 Before disturbing the clutch, use chalk or a marker pen to mark the relationship of the pressure plate assembly to the flywheel. 3 Working In a diagonal sequence, slacken the pressure plate bolts by half a turn at a time, until spring pressure Is released and the bolls can be unscrewed by hand (see Illustration). 4 Prise the pressure piate assembly off its locating dowels, and collect the friction plate, noting which way round the friction plate is fitted (see Illustration).
Inspection Note: Due to the amount of work necessary to remove and refit clutch components, It is usually considered good practice to renew the clutch friction plate, pressure plate assembly and release bearing as a matched set. even if only one of these is actually worn enough to require renewal. It Is also worth considering the renewal of the clutch components on a preventative basis if the engine and/or
6.4 Removing the clutch slave cylinder from the transmission fransmj'ss/on have been removed for some other reason. 5 Separate the pressure plate and friction plate and place them on the bench. 6 When cleaning clutch components, read first the warning at the beginning of this Section; remove dust using a clean, dry cloth, and working in a well-ventilated atmosphere. 7 Check the friction plats facings for signs Of wear, damage or oil contamination. If the friction material is cracked, burnt, scored or damaged, or if It is contaminated with oil or grease (shown by shiny black patches), the friction plate must be renewed. 8 If tho friction material Is still serviceable, check that the centre boss splines are unworn, that the torsion springs are In good condition and securely fastened, and that all the rivets are tight. If any wear or damage is found, the friction plate must be renewed. 9 If the friction material is fouled with oil, this must be duo to an oil leak from the crankshaft rear (left-hand) oil seal, from the sump-to-cytinder block joint, or from the transmission Input shaft. Renew tha soal or repair the Joint, as appropriate, before Installing the new friction plate. 10 Check tha pressure plate assembly for obvious signs of wear or damage; shake it to check for looss rivets or worn or damaged fulcrum rings, and check thai the drive straps securing the pressure plate to the cover do not show signs (such as a deep yellow or blue discoloration) of overheating. If the diaphragm spring is worn or damaged, or if its pressure is In any way suspect, the pressure plate assembly should be renewed.
7.3 Removing the clutch pressure plate bolts 7.4 Removing the clutch pressure plate and friction plate
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7B*4 Automatic transmission
2 Automatic transmission - ^ removal and refitting St
Removal 1 Select a solid, level surface to park the vehicle upon. Give yourself enough space to move around it easily. Apply the handbrake then jack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). Remove both front wheels, 2 Remove the battery and mounting tray as described In Chapter 5A. 3 Remove the air cleaner and air inlet duct as described In Chapter 4A. 4 Disconnect the kickdown cable at the sector on the throttle housing and detach It from the mounting on the camshaft cover. Also release the cable from the support on the left-hand end of the cylinder head. 5 Disconnect the wiring connectors on the transmission. 6 Disconnect the fluid inlet and outlet Unas from the heat exchanger on top of the transmission. 7 Pull the fluid level dipstick from Its tube on the front of the transmission and tape over the top of the tube to prevent dirt entry. 8 Unscrew and remove the retaining pin and disconnect the speed selector cable from the top of the transmission. 9 Unscrew the upper bolt securing the starter motor to the transmission. 10 Unscrew the upper bolts securing the transmission to the engine. 11 Support the weight of the engine using a hoist attached to the engine lifting eyes, or alternatively UBO a trolley jack and block of wood beneath the engine, 12 Remove the screws and remove the front wheel arch liner from under the left-hand wheel arch. 13 Unscrew the nut securing the earth cablo to the transmission. 14 Using a punch drive out the roll pins securing both driveshafts to the final drive output shafts. 15 Unscrew and remove the bolts securing the left-hand swivel hub assembly to the front suspension strut, then separate the components and support the swivel hub on an axle stand. 16 Move the swivel hub assembly outwards and slide the inner end of the driveshaft from the splines on the transmission output shaft. Support the shaft away from the transmission to prevent damage to the gaiters. 17 Unscrew the lambdafoxygen sensor from the exhaust downpipe and position it In a safe place to prevent damage. 18 Unscrew ihe nuts securing the downpipe to Ihe exhaust manifold, then lower It and suppon on an axle stand. Recover the gasket. 19 Unscrew the knurled nut and disconnect the speedometer cable from the top of the final drive housing.
3-2 Locking the flywheel when removing the electromagnetic clutch 20 Unscrew the remaining bolt securing the staner motor to the transmission 21 Unbolt and remove Ihe lower flywheel cover from the transmission. 22 Working beneath the vehicle, unscrew the bolts securing the rear engine mounting to the underbody then unscrew the bolts securing the mounting lo the transmission and withdraw the mounting assembly from under the vehicle. 23 Unscrew the bolts securing the left-hand engine/transmission mounting to the body thon unscrew the bolts from the transmission and remove the mounting. 24 Support the weight of the transmission on a trolley jack then unscrew the remaining nut and bolt from the bellhouslng and pull the transmission away from the engine. Lower it and remove from under the vehicle.
A
Warning: Support the transmission to ensure that It remains steady on the Jack head. Keep the transmission level until the Input shaft and pump shaft are fully withdrawn from the electromagnetic clutch housing.
Refitting 25 Refitting is a reversal of the removal procedure, but note the following points. a} Apply a smear of high-melting-point grease to the splines of the transmission input shaft and oil pump driveshaft.
3.6 Checking the resistance of the clutch windings 1 Slip rings
0) Tighten all nuts and bolts to the
specified
torque, where given, c) Renew both driveshaft roll pins.
3 Electro-magnetic clutch • & removal, inspection 5. and refitting ^
Removal 1 Remove Ihe transmission as described n Section 2. 2 Turn the flywheel so that two of the lour mounting bolts are accessible, Hold tha flywheel stationary then unscrew Ihe tvrt bolts. To hold the flywheel, Insert a wida bladed screwdriver In the ring gear teeth or alternatively use a piece of angle iron against one of the retaining bolts temporarily Inserted in the cylinder block (see illustration). 3 Turn the crankshaft half a turn and unscrew the remaining bolts, then withdraw the electromagnetic clutch.
Inspection 4 Turn the driven element by means of tha slip rings, and check that the bearing is not noisy or rough. 5 Inspect the slip rings for burning or other damage. Clean them if necessary using fid and a clean rag. 6 Check the resistance of the clutch windings, using an ohmmetor connected across the slip rings (see Illustration). The resistance at 20*0 should be 2 to 4 ohms. 7 Check the Insulation of the windings, using an ohmmeter connected between either sip ring and the body of the clutch (see illustration). Resistance should be Infinity. 8 If the clutch fails any of the foregoing checks, renew it. Apart from the brush gear, Individual spares are not available.
Refitting 9 Refitting is a reversal of removal but tighten all bolts to the specified torque.
windings
7B*6 Automatic transmission
Gear selector cable -adjustment
1 Remove the battery and tray as described In Chapter 5A for access to the transmission. 2 Disconnect the selector cable from the lever on Ihe transmission. 3 Move the selector fever inside the vehicle to the N (Neutral) position, then move the lever on the transmission to Its central (Neutral) position. Locate the cable end over the lever. If the cable end fitting does not line up exactly with the hole In Ihe lever, loosen the adjustment nut and reposition the end fitting. 4 With the adjustment correct reconnect tha cable to the lever, then move the selector lever to the P (Park) position. Check that the lever on the transmission has also moved to the P position. 6 Refit the battery and tray as described in Chapter 5A. 6 Road test the vehicle, and check for correct operation in all selector lever positions.
9 Gear selector cable -removal and refitting at
7 Inside the vehicle disconnect the selector cable from the bottom of the selector lever (hen remove it from the support bracket, a Withdraw the cable into the engine compartment, and remove it.
Refitting 9 Refitting is a reversal of removal, but adjust the cable as described in Section 8. 10 Check that It is only possible to start the engine in positions P and N. Reposition the selector lever switch If necessary. 11 Road test the vehicle, and check for correct operation In ell selector lever positions.
10 Transmission oil pump - & mnvtiifll rAtiMlitA removal a/id refitting
Removal 1 Using an Allen key. unscrew the screw and remove the selector lever knob from the lever. 2 Remove the oddment tray and the ashtray. 3 Remove the screws and withdraw the centre console and selector mechanism cover. 4 Unscrew the mounting screws, slightly lift the centre console, then disconnect the wiring and remove the console, 5 Remove the battery and tray as described in Chapter 5A for access to the transmission, 6 Disconnect the selector cable from the lever on the transmission.
Removal 1 Apply the handbrake, then lack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). Remove the left-hand wheel. 2 Unscrew the screws and remove the wheel arch liner. 3 Working through the left-hand wheel arch, remove Ihe three bolts which secure the oil pump. 4 Attach a slide hammer to the oil pump, using the two tapped holes provided. Withdraw the pump using the slide hammer. Be prepared for some oil spillage. Recover the gasket end O-ring (see illustrations). 5 If the pump is defective, it must be renewed; no spares are available.
Refitting 6 Before refitting Ihe oil pump, clean Ihe mating surfaces of the transmission and pump. 7 Rt the oil pump, U9ing a new gasket and a new O-ring. Secure the pump with the three bolts.
8 Refit the wheel arch liner, then refit tto wheel and lower the vehicle to the ground. 9 Check the transmission fluid level » described earlier in this Section, and top-upif necessary.
11 Accelerator pedal & mfcro-Bwftcb(es) -checking
and
adjustment ^
1 Correct adjustment of the micro-awtlch which senses the accelerator pedal position s essential for correct operation of the clutch.
A
quick check can be made by listening for the switch clicking as the accelerator a depressed. For an accurate check, proceed as follows. 2 Disconnect Ihe mlcroswitch wiring connector (nside the vehicle. Connect a continuity tester across the terminals of the switch, located at the top of (he pedal box (see Illustration}. 3 Remove the air cleaner and air ducting as described in Chapter 4A. 4 With the accelerator pedal releassd, th« switch must be closed (zero resistance). Slowty depress the pedal, and check that the switch opens when the throttle valve on the throttle housing is 30° open. This will occur when the pedal has travelled between 3 and 7 mm. Adjust the switch position if necessary. 5 If the switch is permanently open or permanently closed, and adjustment makes no difference, renew ft. 6 Remake the original wiring connections on completion,
12 Automatic transmission -overhaul
Apart from the operations described earlier in this Section, transmission overhaul should be entrusted to a Rat dealer or transmission specialist.
10.4a Using a slide hammer to remove the oil pump from the transmission 10.4b Automatic transmission oil pump O-dng (1), housing (2) and gasket (3) 11.2 Continuity tester connected ecross the accelerator pedal micro-switch
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*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)
Braking system 9®3
2.6a Unscrew the upper...
Petrol models with ABS and diesel models 6 Unscrew the upper and lower caliper guide cin bolts, using a slim open-ended spanner to counterhold the head of the guide pin (see illustrations). Discard the guide pin bolts -new items must be fitted on reassembly. 7 Lift the caliper from the hub/disc assembly (see illustration). Suspend it from a suitable point on the suspension using a length of wire or 8 cable-tie, to avoid straining the hydraulic hose.
All models Caution: Do not depress the brake pedal until the caliper is refitted, or the piston will
be
pushed out of Its bore. 8 Withdraw the brake pads from the caliper bracket (see illustrations). 9 Measure the thickness of each brake pad's foclion material. If either pad is worn at any point to the specified minimum thickness or less, all four pads must be renewed. Also, the pads should be renewed if any are fouled with oil or grease; there is no satisfactory way of degreasing friction material, once contaminated. If any of the brake pads are worn unevenly, or are fouled with oil or grease, trace and rectify the cause before reassembly.
A
Warning: Do not be tempted to swap brake pads over to compensate for uneven wear. 10 if the brake pads are still serviceable, carefully clean them using a clean, fine wire brush or similar and brake cleaning fluid. Pay particular attention to the sides and back of the metal backing. Where applicable, clean out the grooves in the friction material, and pick out any large embedded panicles of dirt
or
debris. 11 Clean the surfaces of the brake pad contact points In the caliper body and caliper mounting bracket. 12 Prior to fitting the pads, check that the giide pins can slide freely in the caliper body, and check that the rubber guide pin gaiters
are
undamaged. Brush the dust and din from
the
caliper and piston, but do not inhale it. as
4 may
contain asbestos. 13 Inspect the dust seal and the area around Ihe piston for signs of damage, corrosion or
models with ABS and diesel models)
brake fluid leaks. If evident, refer to Section 3 and overhaul the caliper assembly. 14 If new brake pads are to be fitted, the caliper piston must be pushed back into the cylinder, to allow for the extra depth of the friction material. Either use a G-clamp or similar tool, or use suitable pieces of wood as levers. Provided that the master cylinder reservoir has not oeen overfilled with hydraulic fluid, there should be no spillage, but keep a careful watch on the fluid level while retracting the piston. If the fluid level rises above the MAX level line at any time, the surplus should be siphoned off. A Warning: Do not syphon the fluid by mouth, as it is poisonous; use a syringe or an old poultry baster. 15 Apply a little high temperature brake grease to the contact surfaces of the pad backing plates: take great care not to allow any grease onto the pad friction linings. Similarly, apply brake grease to the pad contact points on the caliper bracket - again take care not to apply excess grease, which may contaminate the pads. 16 Place the brake pads in position on the caliper bracket, with the friction material facing the surfaces of the brake disc. Feed the wear indicator cable through the caliper body aperture.
Petrol models without ABS 17 Pivot the caliper body down over the brake pads, then refit the guide pin and clip.
2.7 Lift the caliper from the hub/disc assembly
Petrol models with ABS and diesel models 18 Fit the caliper body in position on the caliper bracket, then fit the new guide pin bolts and tighten them to the specified torque.
AH models 19 Check that the caliper body can slide freely on the guide pins. Ensure that the flexible hydraulic hose is not twisted or kinked In any way. Turn the steering from lock to lock and check that the hose does not chafe against the suspension or steering gear. 20 Where applicable, reconnect the pad wear indicator wiring and press it into the retaining clips on the suspension. 21 Repeat the above procedure on the remaining front caliper. 22 With both sets of front brake pads fitted, depress the brake pedal repeatedly until the pads are pressed into firm contact with the brake disc, and normal pedal pressure is restored. Any sponginess felt when depressing the pedal is most probably due to air trapped inside the hydraulic system - refer to Section 11 and bleed the braking system before progressing any further. 23 Refit the roadwheels. and lower the vehicle to the ground. 24 Check the hydraulic fluid level as described in Weekly checks. 25 Check the operation of the braking system thoroughly,
2.8a Withdraw the outboard... 2.8b ... and inboard brake pads from the caliper bracket
9*4 Braking system
3.5 Unscrew the caliper upper guide pin bolt and remove tho caliper body (torn the bracket
3 Front brake caliper -removal, overhaul and refitting ^
A
Warning: Before starting work, refer to the warnings at the beginning of Sections 2 and 11 concerning the dangers of handling asbestos dust and hydraulic fluid.
Removal 1 Chock the rear wheels, apply the handbrake, then |ack up the front of the vehicle and support it on axle stands {see Jacking and vehicle support). Remove the appropriate front roadwheel. 2 Remove the brake pads as described In Section 2. 3 To minimise fluid loss dunng the following operations, remove the master cylinder reservoir cap. then
tig hi en
it down onto a piece of polythene, to obtain an airtight seat. Alternatively, use a brake hose clamp to seal off the flexible hose running to the caliper.
A
Warning: Do not use an ordinary G-clamp or mole grips for this purpose, as these can easily damage the hydraulic hose Internally, possibly leading to failure. 4 Clean the area surrounding the brake hose union, then slacken ft using a ring spanner. It won't be possible to separate the union completely without twisting the hose ai this slage.
3.7 Unscrew the two securing bolts (arrowed) and remove the caliper mounting bracket from the hub carrier
5 On petrol models without ABS, unscrew the caliper upper guide pin bolt using a hex bit or Allen key and remove the caliper body from the bracket (see illustration). 6 Hold the brake hose and rotate the caliper to unscrew the hose union from the caliper body. Cover the open ends of the union and the caliper fluid inlet, to prevent dirt Ingress. Alternatively, Ihe flexible brake hose may be separated from the rigid brake pipe, at the bracket mounted on the Inner wheel arch. 7 If desired, the caliper mounting bracket can be removed from the hub carrier after unscrewing ihe two securing bolts (see Illustration) but note that locking compound must be applied to the bolt threads on refitting.
Overhaul Note: Before commencing work, ensure that the appropriate caliper overhaul kit
Ss
obtained. 8 With the caliper on the bench, wipe away all (races of dust and dirt, but avoid inhaling the dust, as It
Is
a health hazard. 9 Place a small block of wood between the caliper body and tho piston, to act as padding. Remove the piston by applying a Jet of low pressure compressed air (such as that pioduced by a tyre foot pump) to the fluid inlel port.
A
Warning: Protect your hands and eyes when using compressed air In this manner • brake fluid moy be ejected under pressure when the pisfon pops out of Its bore. 10 Peel the dusi seal from the piston, then use a soft, blunt instrument (ie not a screwdriver) to extract the piston seal from the caliper bore. 11 Thoroughly clean all components, U9tng only methylated spint or clean hydraulic fluid, Never use mineral-based solvents such as petrol or paraffin, which will attack Ihe hydraulic system rubber components. 12 The caliper piston seal, the dust seal and the bleed nipple dust cap, a/e oniy available as part of a seat kit. Since the manufacturers recommend that the piston seal and dust seal are renewed whenever they are disturbed, all of these components should be discarded on disassembly and new ones fitted on reassembly as a matter of course. 13 Carefully examine all parts of the caliper assembly, looking for signs of wear or damage. In particular, the cylinder bore and piston must be free from any signs of scratches, corrosion or wear. If there is any doubt about ihe condition of any part of the caliper, the relevant port should be renewed Note that the piston surface is plated, and must not be polished with emery or similar abrasives to remove corrosion or scratches. In addition, the pistons are matched to the caliper bores and can only be renewed as a part of a complete caliper assembly. 14 Check that the threads in the caliper body and the mounting bracket are in good condition, Check that both guide pins are
undamaged, and (when cleaned) a reasons^' tight sliding fit In the mounting bracket bores. 15 UsecompressedairtOblow clear the IkuJ passages. Warning: Wear eye protection when using compressed
air.
16 Before commencing reassembly, en$vr« that all components are spotlessly-clean
and
dry. 17 Soak the new piston seal m clean hydraulic fluid, and fit it to the groove
In
tftt cylinder bore, using your fingers only (rift tools) to manipulate it into place. 18 Fit the new dust seal inner ftp to tne cylinder groove, smear clean hydraulic Hud over the piston and caliper cylinder
bore, and
twist ihe pfaton into the dust seal. Press tne piston squarely Into the cylinder, then sildt the dust seal outer lip to tho groove in we piston
Refitting 19 Where applicable, refit the caliper mounting bracket to thB hub earner. Ccaitto threads ol the mounting bolts with locking compound, then tighten them to the speclfed torque. 20 Hold the brake hose and rotate Ihe calip* to screw the hose union back Into the caliper body. 21 On petrol models without ABS, place the caliper In position on the bracket and tighter the caliper upper guide pin bolt to the specified torque. 22 Relit ihe brake pads as described m Section 2. 23 On all models, tighten the brake hose-to-callper union securely. 24 Check that the caliper slides smoothly
on
its guide pins. 25 Where applicable, remove the polytbste from the master oyhnder rasarvoir cap, or remove tho clomp from the fluid hose, ai applicable. 26 Bleed tho hydraulic fluid circuit as desenbed m Section 11. Note that if rootMf part of the system has been disturbed, < should only be necessary to bleed tha relevant front circuit, 27 Depress the brake pedal repeatedly to bring ihe pads into contact with ihe brake disc, and ensure that normal pedal
pressure is
restored. 28 Refit the roadwheel, and lower tha veti'cfc lo ihe ground.
4 Brake disc -
inspection,
removal
and
refitting
Inspection 1 Firmly apply the handbrake, then jaefcup the front of the car and support It securely
oft
axle stands (see Jacking and vehicle
support1,.
Remove the front roadwhesls.
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Braking system 9®5
2 Rotate the brake disc by hand and examine the whole of the surface area swept by the brake pads, on both sides ot the disc. Note: /( will bo necessary to remove the front brake pads to allow an adequate inspection of the disc's rear surface; refer to Section 2 tor details. 3 Typically, the disc surface will have a polished appearance and should be free from heavy scoring. Smooth rippling is produced by normal operation and does not indicate excessive wear. Deep scoring and cracks, however, are indications of more serious damage in need of correction. 4 If deep scoring Is discovered, it may be possible to have the disc reground to restore the surface, depending on the extent of the damage. To determine whether this is a feasible course of action, it will be necessary to measure the thickness of the disc, as described later. 5 Check the whole surface of the disc for cracks, particularly around the roadwheel bolt holes. A cracked disc mutt be renewed. 6 A ridge of rust and brake dust at the inner and outer edges of the disc, beyond the pad contact area is normal - this can be scraped tway quite easily. 7 Raised ridges caused by the brake pads eroding the disc material, however, are an indication of excessive wear. If close examination reveals such ridges, the oiicknoss of the disc must be measured, to usess whether it is still fit for use. 8 To measure the thickness of the disc, take readings at several points on the surface using a micrometer. In the area swept by the brake pads (see Illustration). Include any points where the disc has been scored: align me Jaws of the micrometer with the deepest ares of scoring, to get a true indication of the extent of the wear. Compare these ineasurements with the limits listed in the Specifications. If the disc has worn below its minimum thickness, at any point, it must be renewed. 9 If the discs are suspected of causing brake luddor, check the disc runout, using one of
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following methods: Runout measurement -
DTI
gauge method 10 Refit the four roadwheel bolts, together
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one M14 plain washer per stud • this will ensure adequate disc to hub contact. Tighten te studs to 5 Nm (4 Ibf ft). 11 Clamp the DTI gauge to a stand and attach the stand, preferably via a magnetic oase. to the strut mounting bracket. Align the jauge so that its pointer rests upon the area of the dtsc swept by the brake pads, on an arc i mm from the outer edge of tho disc (soe illustration). 12 Zero the gauge and slowly rotate the disc trough one revolution, observing tho pointer rcovement. Note the maximum deflection recorded and compare the figure with that >«ted In Specifications.
4.8 Measuring brake disc thickness with a micrometer
Runout measurement -feeler blade method 13 Use the feeler blades to measure the clearance between the disc and a convenient fixed point, such as the disc backplate. Rotate the disc and measure the variation in clearance at several points around the disc, Compare the maximum figure with that listed in Specifications. 14 If the disc runout Is outside of its specified tolerance, first check that the hub Is not worn (see Steering and suspension check in Chapter 1A or 1B). If the hub is In good condition, remove the disc (as described later in this Section), rotate it through 180° and refit it. This may improve the seating and eradicate Ihe excessive runout. 15 If the runout is still unacceptable, then It may be possible to restore the disc by regrinding; consult your Fiat dealer or a machine shop for a professional opinion - it may prove more economical to purchase a new disc. If the disc cannot be reground, then it must be renewed.
Removal 16 Mark the relationship between the disc and the hub with chalk or a marker pen, to allow correct refitting. 17 To allow the disc to be removed, undo the two bolts securing (he brake caliper mounting bracket to the hub carrier (see illustration 3.7). Withdraw the brake caliper and mounting bracket assembly, complete with brake pads, from the hub carrier, and hang it from a rigid point on the suspension, using v/lre or a
4.18a Slacken and remove the disc locating studs ...
4.11 Brake disc runout measurement - DTI gauge method
cable-tie. Oo not allow it to dangle freely as this will strain the brake hose. 18 Slacken and remove the disc locating stud(s). Support the disc as you do this and lift it off as it becomes free (see illustrations). 19 Remove the polished glaze from the surface of the disc with sand/emery paper. Use small, circular motions to avoid producing a directional finish on the surface.
Refitting 20 If a new disc Is being fitted, remove the protective coating from the surface U9ing an appropriate solvent. 21 Locate Ihe disc on ihe hub so that the roadwheel bolt and locating stud holes are all correctly lined up; use the alignment marks made during removal. If the disc is being removed in an attempt to improve seating and hence runout, turn the disc through 180° and then refit it. 22 Refit the locating stud and retaining screw, tightening them securely. 23 Re-check the disc runout, using one of the methods described earlier in this Section. 24 Refil the brake caliper and mounting bracket assembly to the hub carrier. Coat the threads of the mounting bolts with locking compound, then tighten them to the specified torque. 25 Depress the brake pedal several times to bnng the brake pads into contact with the disc. 26 Refit the roadwheel and lower the vehicle to the ground. Tighten the roadwheel bolts to the specified torque. 27 Check the hydraulic fluid level as described in Weekly checks.
4,18b ... and lift off the disc as It becomes free