handbrake FIAT PUNTO 1994 176 / 1.G Owner's Guide
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Page 165 of 225
7A«4 Manual transmission
33 Remove lha air cleaner front section and air ducting with reference to Chapter 4C. Also disconnect the injection pump vacuum pipe from the clips on the left-hand end of the cylinder head. This work is necessary in order to fit the engine hoist 34 Support the weight of the engine using a hoist attached to the engine lifting eyes, or alternatively use a trolley Jack and block of wood beneath the engine. 35 Unscrew the nuts securing the downpipe to the exhaust manifold, then lower it and support on an axle stand. Recover the gasket. 36 Unscrew the starter motor mounting bolts and support the starter motor to one side. 37 Disconnect the wiring from the reversing light switch on the front of the transmission. 38 Unscrew the nut and disconnect the earth cable from its stud. 39 Trace the wiring back from the electronic speedometer sensor and disconnect the connector located on the left-hand side ot the engine. If a mechanical speedometer Is fitted unscrew the knurled collar and disconnect the cabte from the transmission. 40 Unbolt and remove the transmission lower cover. 41 Using an Allen key unscrew the bolts securing the inner end of the left-hand driveshaft to the transmission flange. Remove the bolts and recover the spacer plates. Support the driveshaft on an axle stand. 42 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. 43 Move the swrvel hub assembly outwards and support the driveshaft away from Ihe transmission. 44 Using an Allen key unscrew the bolts securing the Inner end of the right-hand driveshaft to the intermediate shaft flange. Remove the bolts and recover the spacer plates. Support the driveshaft on an axle stand. 45 Remove the intermediate driveshaft with reference to Chapter 8. 46 Working beneath the vehicle, unscrew the bolts securing the rear engine mounting to the underbody then unscrew the bolts securing the mounting to the transmission and withdraw the mounting assembly from under the vehicle.
47 Unscrew the bolts securing the left-hand engine/transmission mounting to the body then unscrew Ihe bolts from the transmission and remove the mounting. 48 Support the weight of the transmission on a trolley jack then unscrew the remaining nut and bolts from the bellhousing and pull the transmission away from the engine.
A
Warning: Support the trans-mission to ensure that It remains steady o/i the jack head. Keep the transmission level until the Input shaft
1$
fully withdrawn from the clutch friction plate.
Refitting 48 Refitting is a reversal of the removal procedure, but note the following points. a) Appiy a smear* of high-meiting-point grease to the clutch friction piate splines; take care to avoid contaminating the friction surfaces. b) Tighten all bolts to the specified torque. c) Fit new clips to secure the driveshaft gaiters to the transmission output shafts. d) Adjust the clutch cable (where applicable) as described In Chapter 6.
4 Manual transmission overhaul -general Infomtatlon
Overhauling a manual transmission is a difficult and Involved Job for the DIY home mechanic. In addition to dismantling and reassembling many small parts, clearances must be precisely measured and, if necessary, changed by selecting shims and spacers. Internal transmission components are also often difficult to obtain, and in many Instances, extremely expensive. Because of this, If the transmission develops a fault or becomes noisy. Ihe best course of action is to have the unit overhauled by a specialist repairer, or to obtain an exchange reconditioned unit. Nevertheless, it is not impossible for the more experienced mechanic to overhaul the transmission, provided the special tools are available, and the Job is done in a deliberate step-by-step manner, so that nothing is overlooked.
The tools necessary for an overhaul include internal and external clrclip pliers, bearing pullers, a slide hammer, a sat of pin punches, a dial test Indicator, and possibly a hydraulic press. In addition, a large, sturdy workbench 8od a vice will be required. During dismantling o1 the transmission, make careful notes of how each component
1$
fitted, to make reassembly easier and more accurate. Before dismantling the transmission, it will help if you have some idea what area is malfunctioning. Certain problems can be closely related to specific areas In the transmission, which can make component examination and replacement easier. Refer to the Fault Finding Section at the end of this manual for more Information.
5 Reversing light switch -testing, removal and refitting ||
Testing 1 The reversing light circuit is controlled by a plunger-type switch screwed into the front of the transmission casing. If a fault develops, first ensure that Ihe circuit fuse has not blown. 2 To test the switch, disconnect the wiring connector, and use a multimeter (set to the resistance function) or a battery-and-bulb test circuit to check that there is continuity between the switch terminals only when reverse gear is selected. If this is not the case, and there are no obvious breaks or other damage to the wires, the switch is faulty, and must be renewed.
Removal 3 Access to the reversing light switch Is best achieved from under the vehicle. Apply the handbrake then jack up Ihe front of the vehicle and support on axle stands (see Jacking and vehicle support). 4 Disconnect the wiring connector, then unscrew It from the transmission casing.
Refitting 5 Refit the switch and tighten securely. 6 Reconnect the wiring then lower the vehicle to the ground.
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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
Page 171 of 225
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
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8*2 Driveshafts
f Outboard CV joint 3 Driveshaft 6 Flange 2 Gaiter clip A Garter 6 Inboard CV ioint
1.2 Intermediate driveshaft • turbo diesel models 1 Bearing flange 3 Washer S Retaining plate 2 Bearing A Circllp
2.S Extracting the driveshaft from the hub (arrowed) from the CV joint at the carrier transmission
The joints are protected by rubber g&itcrs and are packed with grease, to orovktt permanent lubrication. If wear Is detected in the joint. It can be detached from lii» driveshaft and renewed. Normally, the CV joints do not require additional lubrication, unless they havo been overhauled or lfi» rubber gaiters have been damaged, allotting the greasa to become contaminated. Rater
to
Chapter 1A or 1B for guidance In checking the condition of the driveshaft gaiters. Bolh driveshafts are splined at their outer ends, to accept the wheel hubs, ond ate threaded so that the hubs can be fastened to the driveshafts by means of a large, staked nut.
2 Driveshafts -removal and refitting & ^
Note: A balljoint separator tool will b» required for this operation. A new drivestnf, nut and tmck-rod end nut should be used
on
refitting. In addition, new lower arm
baHj&ot
nuts should be used. Removal 1 Chock the rear wheels, apply the handbrake, then jack up the front of tha vehicle and support on axle stands (see Jacking and vehicle support). Remove th« appropriate roadwheel(6). 2 The front hub must be held stationary
m
order to loosen the driveshaft nut. Ideally, M hub should be held by a suitable tool bolted Into placo using two of the roadwheel nuts, Alternatively, havo an assistant firmly apply the brake pedal to prevent the hub from rotating. Using e socket and extension bar, slacken and remove the driveshaft nut. Recover the washer (where fitted).
A
Warning: The nut Is extremely tight. Discard the nut - a new
one
must be used on refitting. 3 Remove the locking clip and extract the brake caliper hydraulic hose (and where applicable, the brake pad wear indicator cable) from the bracket on the base of the suspension strut. 4 With reference to Chapter 10, Section 3. unbolt the base of the suspension strut from Ihe top of the hub carrier. 5 Temporarily refit the driveshaft nut to the end of the driveshaft, to prevent damage to the driveshaft threads, then using a solt-faced mallet, carefully tap the driveshaft from the hub carrier (see illustration). If the shaft is a tight fit, a suitable hub puller can be used to force the end of the shaft from the hub. Support tha end of the driveshaft • do not allow the end o the driveshaft to hang down as this svill strain the joint components and gaiters. 6 Proceed as follows, according to which driveshaft is to be removed. All models except turbo diesels 7 Remove the driveshaft gaiter clip from the CV joint at the transmission (see Illustration)
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I
8*4 Driveshafts
3.3 Using pair of circlip pliers, expand the circlip that holds the driveshaft in place
Turbo diesel models 4 Mark the relationship between the joint and the driveshaft using a scriber or a dab of paint. Attach a slide hammer to the dnveshaft nut thread. 5 Draw the joint off the driveshaft using the slide hammer, Use just enough effort to overcome the tension of the internal circlip.
Inboard CV joint removal All models except turbo dieseis 6 Al the inboard end of the driveshaft. use a hammer and centre punch to mark the relationship between Ihe shaft and |olnt. Remove the circlip with a pair of circlip pliers, then using a three-legged puller if required, draw Ihe tripod joint off the end of the driveshaft. Ensure that the legs of Ihe puller bear upon the cast centre section of the joint, not the roller beanngs (see illustration) Turbo diesel models 7 Al the inboard end of Ihe driveshaft. use a hammer and centre punch lo mark the relationship between the shaft and joint. Remove the circlip with a pair of circlip pliers, then carefully slide the CV joint from the end ot the shaft. Take great care to prevenl the
cage and bail bearings from falling out • secure the joint components together with wire or a nylon cable-tie. 8 Remove the washer then slide the flange from the end of the shaft.
Inspection 9 Slide both rubber gaiters off the driveshaft and discard them: It is recommended that new ones are fitted on reassembly as a matter of course. Recover the flexible washers (where fitted), making a note of their fitted positions, to aid correct refitting later. 10 Thoroughly clean the driveshaft splines, and CV joint components with paraffin or a suitable solvent, taking care not to destroy any alignment marks made during removal. 11 Examine Ihe CV joint components for wear and damage: in particular, check the balls and corresponding grooves for pitting and corrosion. If evidence of wear Is visible, then the joint must be renewed. Note that if the outboard CV joint Is to be renewed on turbo diesel models, it must be matched to the driveshaft using the colour-coded paint markings. 12 Where applicable, examine the tripod joint components for wear. Check thai the three rollers are free lo rotate without resistance and are not worn, damaged or corroded. The rollers are supported by arrays of needle bearings: wear or damage will show up as play In the rollers and/or roughness in rotation. If wear is discovered, the tnpod joint must be renewed. 13 Fit a new rubber gaiter (and where applicable, flexible washer) to the inboard end of the driveshaft and secure it In place on the shaft with a clip (see illustration).
Inboard CV joint - refitting
All models except turbo dieseis 14 Using Ihe alignment marks made during removal, fit the tripod joint onto the splines of the driveshaft. Tap It Into position using a soft faced mallet. To ensure that the tripod Joint rollers and driveshaft splines are not damaged, use a socket with an internal diameter slightly larger than I hat of the driveshafl as a drift. Refit the circlip. 15 Slide the gaiter over tho tripod joint and pack the gaiter with grease from the service kit.
3.6 Draw the tripod joint off the end of the driveshaft 3.13 FH s new rubber gaiter to the inboard end of the driveshaft and secure It in place with a clip
Caution: Do not allow grease to come
into
contact with vehicles paintwork, es discolouring may rasutt. Turbo diesel models 16 Slide the flange and washer onto the end of the shaft, then fit the joint Into position on the driveshaft splines, using the alignment marks made during removal. Fit the circlip. ' 17 Pack the gaiter with grease from His service kit, then slide the gaiter over the joint. Briefly lift the lip of the gaiter to expel ail the air from the joint, then secure the gaiter over the joint with a new clip. Caution: Do not allow grease to come
Into
contact with the vehicle's paintwork, as discolouring may result.
Outboard CV joint - refitting 18 Fit a new rubber gaiter to the outboard end of the driveshaft and secure it place with a dp, 19 Pack the CV joint with grease from Ihe service kit, pushing It into the ball grooves and expelling any air that may be trapped underneath. 20 Lubricate the splines of the drive shaft with a smear of grease, then whilst splaying the circlip open with a pair ot circlip pile*, insert the driveshaft into CV joint, observing the alignment marks made during removal. Note: On turbo diesel models, the circlip snaps into the CV Joint groove as Ifte driveshaft is inserted - no circlip pliers are required. Ensure that the circlip snaps securely Into place: pull on the shaft to check that it is held firmly In position. 21 Pack additional grease Into the joint to displace any air pockets, then slide the rubber gaiter over the joint. Briefly lift the lip ol the gaiter to expel all the air from Ihe joint, then secure it In place with a clip. 22 Refit the driveshaft (see Section 2).
4 Intermediate driveshaft - % removal and refitting J;
Note 1: This procedure applies only to turbo diesel engined models. Note 2: The intermediate shaft and
bearing
are not available as separate spares and cac only be renewed as a comptefe assembly.
Removal 1 Firmly apply the handbrake, then jack up the front of Ihe car and support It securely
on
axle stands (see Jacking and vehicle support). Remove the appropriate roadwheei(s). 2 Unbolt the inboard end of the right*hand driveshaft from the intermediate shaft
flange, as
described In Section 2. Suspend the dis-connected end of the driveshaft from a conven-ient point on the subframe, using wire or a cable-tie. to avoid straining the joint and gaiter. 3 Drain the oil from the transmission, with reference to Chapter 1B.
Page 177 of 225
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
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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)
Page 180 of 225
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.
expert22 f
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Page 182 of 225
9*6 Braking system
5.4a Detaching the tower return spring
S Rear brake shoes -renewal ji,
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Warning: Renew BOTH sets of rear brake shoos at the same time • NEVER renew the shoes on onty one wheel, as uneven braking may result.
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Warning: Before sterling work, refer to tho warning given at the beginning of Section 2, concerning the dangers of asbestos dust. 1 Remove the rear brake drums, as described In Section 6. 2 Working on one side ot the vehicle, brush the dirt and dust tram tho brake backpiate and drum. Avoid inhaling the dust, as it may contain asbestos, which Is a health hazard, 3 Note the position of each shoe, and the location of the return and steady springs. Also
5.6 Unhook the self-adjuster mechanism roturn spring from the leading brake shoe
5.7b ... and remove it
5.4b Detaching the upper return spring from tho leading ...
make a note oi the adjuster component locations, to aid refitting later. Il is advisable, at this stage to wrap a stout rubber band or a cable-tie over Ihe wheel cylinder, to prevent the pistons from being accidentally ejected. 4 Detach tha upper and lower return springs from both brake shoes (see illustrations). 5 Unhook the sell-adjuster mechanism return spring Iroin the leading brake shoe (see illustration). Remove the hold-down cup and spring from the leading shoe. The spring cups are a bayonet-style fit • use a large pair of pliers to depress and Ihen turn the cup through 90", while holding Ihe pin from behind the backpiate. Remove the pin. 6 Carefully pull the leading brake shoe away from the backpfaie and remove It (see Illustration). 7 Using a suitable pair of pliers, unhook the self-adjuster mechanism from the trailing shoe and remove it (see Illustrations).
away from the backpiate and remove it
5.8a Remove the hold-down cup and spring from the trailing shoe
5.4c ... and trailing brake shoes
8 Remove the hold-down cup and spring from the trailing shoe, using a large pair of pliers, as described for the leading shoe. Remove the pin. Lift the trailing shoe away from the backpiate and disconnect the handbrake cable from the brake shoe lever (see illustration). 9 Thoroughly ciean the surface of tru-backpiate using brake component cleaner lo remove all traces of dust and old lubricant. Examine all components for signs o4 corrosion. 10 Apply brake grease sparingly to the shoe contact surfaces of tho brake backpiate (see Illustration). 11 Connect tha handbrake cable to the Iwr on the trailing brake shoe, locate the trailing shoe on the backpiate and secure In position with the pin, hold down spring and cup. Usnj pliers, turn the cup through 90" and men release It. to lock it in position.
5.7a Unhook the solf-adjuster mochanism from the trailing shoe...
5.6b Lift the trailing shoe away from the backpiate...
Page 183 of 225
Braking system 9®7
5JJc ... and disconnect the handbrake cable from the brake shoe lever
5.14a Lower return spring fitted in place
12 Fit the self-adjuster mechanism Into the recess in the trailing brake shoe and anchor the retaining spring in the slot provided in the shoe (see Illustration). 13 Fit the leading shoe In position on the backpiste and secure it with the hold down pin. spring and cup as described for the trailing shoe. Engage the end of'the self-adjuster mechanism with the recess In the leading brake shoe. Hook the retaining spring into the slot provided. 14 Fit the upper and lower shoe return spnngs. engaging them with the slots In the shoes as shown (see illustrations). Remove
me
elastic band from the wheel cylinder. 15 Turn Ihe serrated wheel at the end of the self-adjuster mechanism, to retract the brake shoes - this will give additional clearance to ilow Ihe drum to pass over the shoes during refitting. 16 Repeat the procedure on the remaining tide of the vehicle. 17 Refit the brake drums as described in Section 6. Check and if necessary adjust the operation of the handbrake, as described in Section 9. IB Apply the brake pedal and handbrake 'ever several times to settle the self-adjusting mechanism. With both rear roadwheels rsfitted and Ihe rear of the vehicle still raised, turn Ihe wheels by hand to check that the take shoes are not binding. 19 Lower the vehicle to the ground and thoroughly check the operation of the braking system.
5.10 Apply brake grease sparingly to the shoe contact surfaces (arrowed) of the brake backplate
5.14b Correct location of upper return spring In leading shoe...
6 Rear brake drums -removal, inspection and refitting ^
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Warning: Before starting work, refer to the warning at the beginning of Section 2 concerning the dangers of asbestos dust Removal 1 Chock the front wheels, then jack up the roar of the vehicle and support it on axle stands (see Jacking and vehicle support). Remove the appropriate rear roadwheel. Fully release the handbrake. 2 If the original drum is to be refitted, mark the relationship between the drum and the hub. Slacken and remove the two locating studs and pull the drum from the hub (see illustration).
6.2 Slacken and remove the two drum locating studs
5.12 Fit the self-adjuster mechanism into the recess (arrowed) in the trailing brake shoe
5.14c ... and trailing shoe
3 If the drum is binding on Ihe brake shoes, it can be drawn off as follows. Hold the drum still and turn the hub so that the drum and hub flange bolt holes no longer line up. Screw two bofts into the locating stud threaded holes In tho drum, and progressively lighten them against the hub llange to push the drum from the hub (see illustration).
Inspection Note: If either drum requires renewal, BOTH should be renewed at the same time, to ensure even and consistent braking. New brake shoes should also be fitted. 4 Working carefully, remove all traces of brake dust from the drum, but avoid Inhaling the dust, as it is a health hazard. 5 Clean the outside of the drum, and check it for obvious signs of wear or damage, such as cracks around the roadwheel stud holes; renew the drum if necessary.
6.3 Using two bolts to draw the drum off the brake shoes