ABS FIAT PUNTO 1995 176 / 1.G Owner's Manual
[x] Cancel search | Manufacturer: FIAT, Model Year: 1995, Model line: PUNTO, Model: FIAT PUNTO 1995 176 / 1.GPages: 225, PDF Size: 18.54 MB
Page 143 of 225
Fuel system - diesel models 4C*3
14.6 Nuts securing the exhaust downpipe to the exhaust manifold 14.8 Disconnecting the oil return pipe from tho turbocharger
13 Turbocharger -description and precautions
Description A turbocharger 1$ fitted to TDS, TD and SX models. It increases engine efficiency by raising the pressure In the inlet manifold above atmospheric pressure. Instead of the air simply being sucked Into the cylinders. It Is forced in. Additional fuel is supplied by the injection pump in proportion to the increased air inlet. Energy for the operation of the turbocharger comes from the exhaust gas. The gas flows through a specially-shaped housing (the turbine housing) and In so doing, spins the turbine wheel. The turbine wheel is attached lo a shaft, at the end of which is another vaned wheel known as the compressor wheel, The compressor wheel spins in Its own housing, snd compresses the inlet air on the way to the inlet manifold. Boost pressure (the pressure in the Inlet manifold) is limited by a wastegate, which diverts Ihe exhaust gas away from the turbine wheel In response to a pressure-sensitive actuator. A pressure-operaled switch operates a warning light on the instrument panel in the event of excessive boost pressure developing. The turbo shaft is pressure-lubricated by an oil feed pipe from the main oil gallery The shaft floats on a cushion of oil. A drain pipo returns the oil to the sump.
Precautions The turbocharger operates at extremely high speeds and temperatures. Certain precautions must be observed, to avoid premature failure of the turbo, or injury to the operator. Do not operate the turbo with any of its parts exposed, or with any of ils hoses removed. Foreign objects falling onto the rotating vanes could cause excessive
damage, and (if ejected) personal injury. Do not race the engine immediately after start-up, especially if it Is cold. Give the oil a few seconds lo circulate. Always allow the engine to return to idle speed before switching il off - do not blip the throttle and switch off, as this will leave the turbo spinning without lubrication. Allow the engine to idle lor several minutes before switching off after a high-speed run. Observe the recommended intervals for oil and filter changing, and use a reputable oil of the specified quality. Neglect of oil changing, or use of Inferior oil, can cause carbon formation on the turbo shaft, leading to subsequent failure.
14 Turbocharger -removal and refitting
8 Disconnect the oil return pipe from the turbocharger (see Illustration). 9 Unscrew the bolt securing the mounting bracket to the cyfindar block. 10 Unscrew the mounting nuts and withdraw the turbocharger from the studs in Ihe exhaust manifold. Recover the gasket. II It Is to be refitted, store the turbocharger carefully, and plug its openings to prevent dirt ingress.
Refitting 11 Refitting Is a reversal of removal, bearing in mind the fallowing points: a) if a new turbocharger Is being fitted, change the engine oil and filter. b) Tighten ail nuts and bolts to the specified torque. c) Before starting the engine, prime the turbo lubrication circuit by disconnecting the stop solenoid iead at the injection pump, and cranking the engine on the starter for three ten-second bursts.
Removal 1 Remove the battery as described in Chapter 5A. 2 Unbolt and remove the relay guard and bracket from the left-hand side of Ihe engine. 3 Remove the air cleaner and ducting as descnbed in Section 2. 4 Loosen the clips and remove the air outlet duct between tho turbocharger and inlet manifold. Also disconnect the air inlet duct from the turbocharger. 6 Appty the handbrake, then jack up tho front of the vohicle and support on axle stands (see Jacking and vehicle support). 6 Bend back the locking tabs (if fitted) and unscrew the nuts securing the exhaust downpipe lo the exhaust manifold (see Illustration). Disconnect the downpipe from the exhaust system (refer to Part 4D) end remove it from under the vehicle. Recover tne gasket. 7 Unscrew ihe union nut and disconnect the oil supply pipe from the turbocharger. Recover the copper ring and tape over the end of the pipe 10 prevent dust entry.
15 Turbocharger -examination and renovation l
1 With the turbocharger removed, inspect the housing for cracks or other visible damage. 2 Spin the turbine or the compressor wheel, to verify that the shaft is intact and to feel for excessive shake or roughness. Some play is normal, since in use, the shaft is floating on a film of oil. Check that the wheel vanes are undamaged. 3 The wastegate and actuator are Integral, and cannot be checked or renewed separately. Consul! a Flat dealer or other specialist If it is thought that testing or renewal is necessary. 4 If tho exhaust or induction passages are ail* contaminated, Ihe turbo shaft oil seals have probably failed. 6 No DIY repair of the turbo is possible. A new unit may be available on an exchange basis,
Page 146 of 225
4D*3 Exhaust and emission control systems
Refitting 8 Refitting is a reversal of the removal pro-cedure but fit new gaskets. Tighten the nuts lo the specified torque.
Diesel models Note: On diesel models the inlet and exhaust
manifolds
are located on the rear of the engine
end
share the same securing nuts and gasket. Removal 8 Remove the inlet manifold as described In Part
C
of this Chapter. 10 Firmly apply the handbrake, then jack up lite front of tho car and support it securely on axle stands (see Jacking and vehicle support). 11 Straighten the tab washers (where fitted), then unscrew and remove the exhaust downpipe retaining nuts. Detach the downpipe from the manifold/turbocharger. Suitably support the downpipe. 12 Undo the manifold-to-cylinder head securing nuts and withdraw the manifold (see Illustration). 13 Separate the turbocharger from the manifold with reference to Chapter 4C. 14 Remove the gasket and clean the mating
(aces
of the manifold, cylinder head and down-pipe flange (see illustration). The gasket must
be
renewed when refitting the manifold, Refitting
15 Refitting is a reversal of the removal procedure but fit a new gasket. Tighten the retaining nuts to the specified torque and where necessary lock them by bending over
the
tocktabs.
6 Exhaust system - % general information and ^ component renewal
Genera/ Information 1 A three section exhaust system is fitted consisting of a twin-branch front downpipe, a catalytic converter, and a tailpipe with two silencers. The downpipe-to-manifold and downpipe-to-catalytic converter joints are both of flange and gasket type, whereas the remaining joint Is of the sleeve type secured
witn
a clamp ring (see illustration). 2 The system is suspended throughout its entire length by rubber mountings.
Removal 3 Each exhaust section can be removed individually or, alternatively, the complete system can be removed as a unit. Where separation of the rear sleeve Joint is necessary, it may be more practical to remove
the
entire system rather than try and separate
the Joint
In position. 4 To remove the system or part of the system, first jack up the front of the vehicle and support on axle stands (see Jacking and nhlcle support), Alternatively position the
vehicle
over an inspection pit or on car ramps.
5.12 Removing the exhaust manifold (diesel engine) Downpipe 5 Support the catalytic converter using an axle stand or blocks of wood. Where applicable on petrol models, refer to Section 4 and remove the oxygen sensor from the exhaust downpipe. 6 Unscrew and remove the bolts securing the downpipe to tha catalytic converter, then separate the joint and recover the gasket. 7 Bend back the locktabs (where fitted) then unscrew the nuts securing the downpipe to the exhaust manifold/turbocharger. and lower the downpipe, Recover the gasket. Catalytic converter
8 Support the tailpipe section of the exhaust using an axle stand or blocks of wood. 9 Unscrew and remove the bolts securing the downpipe to the catalytic converter, then separate the joint and recover the gasket. 10 Unscrew the clamp bolt and separate the converter from the tailpipe section. 11 Release the mounting rubber and remove the converter from under the vehicle. Tailpipe and silencers 12 Support the catalytic converter using an axle stand or blocks of wood. 13 Unscrew the clamp bolt and separate the catalytic converter from the tailpipe section. 14 Release the tailpipe section from its mounting rubbers and remove from under the vehicle. Complete system 15 Disconnect the downpipe from the ex-haust manifold as described in paragraph 7.
6.1 Exhaust clamp ring securing the tailpipe to the front exhaust system
5.14 Removing the oxhaust manifold gasket (diesel engine) 16 With the aid of an assistant, free the system from all its mounting rubbers and manoeuvre it out from underneath the vehicle. Heatshield 17 The heatshield is secured to the underbody by bolts and Is easily removed once the exhaust system has been removed.
Refitting 18 Each section is refitted by a reverse of the removal sequence, noting the following points. a) Ensure that all traces of corrosion have been removed from the flanges and renew ail necessary gaskets. b) Inspect the rubber mountings for signs of damage or deterioru tion and renew
as
necessary. c) Before refitting the tailpipe joint, smear some exhaust system jointing paste to the joint mating surfaces to ensure an air-tight seal. Tighten the clamp bolt. d) Prior to fully tightening the rear joint damp, ensure that all rubber mountings are correctly /ocafed and that there is adequate clearance between the exhaust system and vehicle underbody.
7 Catalytic converter -general information and precautions
The catalytic converter is a reliable and simple device which needs no maintenance In itself, but there are some facts of which an owner should be aware if the converter is to function properly for its full service life.
Petrol models a) DO NOT use leaded petrot In a car equipped with a catalytic converter - Ihe lead will coat the precious metals, redudng their converting efficiency
and
will eventually destroy the converter. b) Always keep the ignition and fuel systems well-maintained in accordance with the manufacturer's schedule. c) If the engine develops a misfire, do not drive the car at all (or at least as little
as
possible) until the fault is cured.
Page 159 of 225
6*2 Clutch
3 Clutch cable -removal and refitting
Note: This procedure applies to models fitted with a cabfe-opemted dutch
release mechanism.
Removal 1 Remove the battery and tray as described In Chapter SA. If necessary, also remove the Inlet air ducting for Improved access as described In the relevant part of Chapter 4. 2 Unscrew the adjustment locknut and adjuster nut from the end of the cable fitting, (hen release the inner and outer cables from the transmission housing. Note the position of the damper biock. 3 Working Inside the vehicle, unhook the inner cable from the top of the clutch pedaL 4 Returning to the engine compartment, unscrew the nuts securing the outer cable to the bulkhead, then withdraw the cable assembly from the engine compartment. Refitting 5 Apply a smear of multi-purpose grease to the cable end fittings, then pass the cable through the bulkhead. Refit and tighten the nuts. 6 Inside the vehicle hook the inner cable onto the top of the clutch pedal. 7 in the engine compartment, attach the outer cable to the transmission housing and refit the damper block and nuts lo Ihe inner cable end. fi Adjust the cable as described in Section 2. 9 Refit the air ducting and battery with reference to Chapters 4 and 5A
4 Clutch hydraulic system -
i
Note: This procedure applies to models fitted with the hydraulicalty-operated clutch release mechanism.
A
Warning: Hydraulic fluid Is poisonous; thoroughly wash off spllfs from bare skin without delay. Seek Immediate medical advice If any fluid is swallowed or gets into the eyes. Certain types of hydraulic fluid are Inflammable and may ignite when brought into contact with hot components; when servicing any hydraulic system, It is safest to assume that the fluid IS Inflammable, and to take precautions against the risk of fire as though ft were petrof that was being handled. Hydraulic fluid Is an effective paint stripper and will also attack many plastics. If spillage occurs onto painted bodywork or fittings, ft should be washed off Immediately, using copious quantities of fresh water. It Is also hygroscopic - It can absorb moisture from the air, which then renders it useless. Old fluid may have
suffered contamination, and should never be re-used. When topping-up or renewing tho fluid, always use tha recommended grade, and ensure that It comes from a new seated container. General information 1 Whenever the clutch hydraulic lines are disconnected for service or repair, a certain amount of air will enter the system. The presence of air In any hydraulic system will Introduce a degree of elasticity, and in the clutch system this will translate into poor pedal feel and reduced travel, leading to inefficient gear changes and even clutch system failure. For this reason, the hydraulic lines must be sealed using hose clamps before any work la carried out and then on completion, topped up and bled to remove any air bubbles. 2 To seal off Ihe hydraulic supply to tha clutch slave cylinder, fit a proprietary brake hose clamp to the flexible section of the hose located over the transmission and tighten it securely. It will be necessary to remove the battery and battery tray to access the hose. 3 The most effective way of bleeding the clutch hydraulic system is to use a pressure brake bleeding kit. These are readily available in motor accessories shops and are extremely effective: the following sub-section describes bleeding the clutch system using such a kit. The alternative method is to bleed the system by depressing tho clutch pedal • refer to Chapter 9. Section 11, for details of this method.
Bleeding 4 Remove the protective cap from Ihe bleed nipple on the slave cylinder. Access can be improved by removing the battery and tray with reference to Chapter 5A. 5 Fit a ring spanner over the bleed nipple head, but do not slacken it at this point. Connect a length of dear plastic hose over the nipple and insert the other end into a clean container. Pour hydraulic fluid into the container, such that the end of the hose is covered. 6 Following the manufacturer's instructions, pour hydraulic fluid into the bleeding kit vessel 7 Unscrew the vehicle's fluid reservoir cap, then connect Ihe bleeding kit fluid supply hose to the reservoir. 8 Connect the pressure hose to a supply of compressed air - a spare tyre is a convenient source. Caution: Check that the pressure In the tyre does not exceed the maximum supply pressure quoted by the kit manufacturer, let soma sir escape to reduce the pressure, if necessary. Gently open the air valve and allow the air and fluid pressures to equalise. Check that there ere no teaks before proceeding. 9 Using the spanner, slacken the bleed pipe nipple until fluid and air bubbles can be seen to flow through the tube, into the container.
Maintain a steady flow until the emerging fluid la free of air bubbles; keep a watchful eye on the level of fluid in the bleeding kit vessel and the vehicle's fluid reservoir • if it Is allowed to drop too low, air may be forced into the system, defeating the object of the exercise. To refill the vessel, turn off the compressed air supply, remove the lid and pour In en appropriate quantity of clean fluid from a new container - do not re-use the fluid collected in the receiving container. Repeat as necessary until the ejected fluid is bubble-free. 10 On completion, pump the olutch pedal several times to assess its feel and travel. If firm, constant pedal resistance is not felt throughout the pedal stroke, it i6 probable that air Is still present in the system - repeat the bleeding procedure untii the pedal feel is restored. 11 Depressurise the bleeding kit and remove it from the vehicle. At this point, the fluid reservoir may be over-full; the excess should be removed using a clean pipette to reduce the level to the MAX mark. 12 Tighten the bleed pipe nipple using the spanner and remove the receiving container. Refit the protective cap. 13 On completion, assess the feel of the clutch pedal; if it exhibits any sponginess or looseness, further bleeding may be required. 14 Where removed, refit the battery and tray. 15 Finally, road test the vehicle and check the operation of the clutch system whilst changing up and down through the gsar9. whilst pulling away from a standstill and from a hill start.
5 Clutch master cylinder - & removal
and
refitting 5 S Note: This procedure applies to models
fitted
with the hydraulically-operated dutch
release
mechanism. Note: Refer to the warning at Ihe beginning
of
Section 4 regarding the hazards of
working
with hydraulic fluid.
Removal 1 Disconnect the battery negative terminal (refer lo Disconnecting the battery in the Reference Section of this manual). 2 Remove the air cleaner and air ducting as described in the relevant Part of Chapter 4. 3 For improved access on petrol engine models, remove the alternator as described In Chapter 5A. 4 Fit a brake hose clamp to the hose between the hydraulic fluid reservoir and the clutch master cylinder. Alternatively syphon ail the fluid from the reservoir. 5 Disconnect the fluid supply hose at the master cylinder, then unscrew the union nut and disconnect the hydraulic pipe from the cylinder outlet. Be prepared for some fluid loss by placing some rags beneath the master cylinder.
Page 178 of 225
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 179 of 225
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
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
a http://rutracker.org
Page 186 of 225
9*10 Braking system
10.6 Disconnect the relevant handbrake inner cable (arrowed) from the draw bar 6 Working inside ihe vehicle, remove Ihe screws and lift off the handbrake lever trim panel (refer to Section 9 for more detail). At the base of the handbrake lever, full/ slacken off the handbrake adjusting screw and locknut, to remove oil tension from the cable draw bar, then disconnect the relevant handbrake inner cable from the cable draw bar (see illustration) 7 Release the cable grommet from tho floor-pan, then withdraw the cable from the vehicle.
Refitting 8 Refitting Is a reversal of removal, bearing in mind the following points: a) Ensure that the cables are securely fastened In the clips on the floorpan beetshield and lower suspension a/m. b) On completion, check the handbrake adiustment, as described in Section 9.
11 Hydraulic system -bleeding
A
Warning: Hydraulic fluid is poisonous; wash off immediately and thoroughly In the case ot skin contact, and seek immediate medical advice if any fluid is swallowed, or gets into the eyes. Certain types of hydraulic fluid are Inflammable, and may ignite when allowed into contact with hot components. When servicing any hydraulic system, it Is safest to assume that the fluid IS inflammable, and to take precautions
11.17 Bleeding a rear brake line
against the risk of fire as though it is petrol that Is being handled. Hydraulic fluid is also an effective paint stripper, and will attack plastics; If any is spilt, It should be washed off immediately, using copious quantities of fresh water. Finally, it Is hygroscopic (it absorbs moisture from the air) • old fluid may be contaminated and unfit tor further use. Whan topping-up or renewing the fluid, always use the recommended type, and ensure that It comes from a freshly-opened sealed container.
General 1 The correct operation of any hydraulic system is only possible after removing all air from the components and circuit; and this Is achieved by bleeding the syslem. 2 During the bleeding procedure, add only clean, unused hydraulic fluid of the recommended type; never re-use fluid that has already been bled from the system. Ensure that sufficient fluid is available before starting work. 3 If there is any possibility of incorrect fluid being already in the system, the brake com-ponents and circuit must be Flushed completely with uncontamlnated, correct fluid, and new seals should be fitted throughout the system. 4 If hydraulic fluid has been lost from the system, or air has ontered because of a leak, ensure that the fault is cured before proceeding further. 5 Park Ihe vehicle on level ground, switch off the engine and select first or reverse gear (or P), then chock the wheels and release the handbrake. 6 Cheek that all pipes and hoses are secure, unions tight and bleed screws closed. Remove Ihe dust caps (whore applicable), and clean any dirt from around the bleed screws. 7 Unscrew the master cylinder reservoir cap, and top Ihe master cylinder reservoir up to the MAX level line; refit the cap loosely. Rememoer to maintain the fluid level at least above the MIN level line throughout the procedure, otherwise there is a risk of further air entering the syslem. 8 There are a number of one-man. do-It-yourself brake bleeding kits currently available from motor accessory shops. It is recommended that one of these kits is used whenever possible, as they greatly simplify the bleeding operation, and also reduce the risk of expelled air and fluid being drawn back into the system. If such a kit is not available, the basic (two-man) method must be used, which is described in detail below. 9 If a kit Is to be used, prepare the vehicle as described previously, and follow the kit manufacturer's instructions, as Ihe procedure may vary slightly according to the type being used; generally, they are as outlined below in the relevant sub-section. 10 Whichever method is used, the same sequence must be followed (paragraphs 11 and 12) to ensure Ihe removal of all air from the system.
Bleeding sequence 11 If Ihe system has been only
partial!?
disconnected, and suitable precautions wwe taken to minimise fluid loss, it should be necessary to bteod only that part of the system (le the primary or secondary circuit). 12 If the complete system Is to be bled, then It should be done working in the following sequence: a) Left-hand rear wheel b) Right-hand front wheel. c) Right-hand rear wheel. d) Left-hand front wheel. Note: When bleeding the rear brakes
on a
vehicle ritled with load proportioning valves: i the rear of the vehicle has been jacked
up to
allow access to ihe brake wheel cylinder,
tha
rear suspension must be compressed
(eg
raising the beam axle with a trolley
jack) so
that the load proportioning valves
remain open
throughout the bleeding process.
Bleeding -basic (two~man) method 13 Collect a clean glass jar, a suitable length of plastic or rubber tubing which Is a light fit over the bleed screw, end a ring spanner lo
Rt
the screw. The help of an assistant will also tie required. 14 Remove the dust cap from the first screw In the sequence if not already done. Fit a suitable spanner and tube to the screw, place the other end of Ihe tube In the jar. and
pour in
sufficient fluid to cover the end of the tube. 15 Ensure that the master cylinder reservoir fluid level is maintained at least above the
MIN
level line throughout the procedure. 16 Have the assistant fully depress the brefce pedal several times to build up pressure, then maintain it on the final downstroke. 17 While pedal pressure is maintained, unscrew ihe bleed screw (approximately one turn) and allow the compressed fluid and orto flow into the
Jar,
The assistant should maintah pedal pressure, following the pedal down to the floor if necessary, and should not rrtaase Ihe pedal until instructed to do so. When ihe flow stops, tighten the bleed screw again, have the assistant retease the pedal sfowty, and recheck the reservoir fluid level (see Illustration). 18 Repeat Ihe steps given in paragraphs 16 end 17 until the fluid emerging from the bled screw is free from air bubbles. If Ihe master cylinder has been drained and refilled,
and
at Is being bled from the first screw In the sequence, allow approximately five seconds between cycles for the master cylinder passages to refill. 19 When no more air bubbles appear, tighter, the bleed screw securely, remove Ihe tube arc spanner, and refit the dust cap (where applicable). Do not overtighten the bleed sew. 20 Repeat the procedure on tho remaining screws In the sequence, until ail air is removed from the system, and the brake pedal feels firm again.
Page 187 of 225
Braking system 9®11
Bleeding • using a one-way valve kit 21 As their name implies, these kits consist ol a length of tubing with a one-way valve Fitted, to prevent expelled air and fluid being drawn back into the system; some kits include a translucent container, which can be positioned so that the air bubbles can be more easily seen flowing from the end of the tube. 22 The kit is connected to the bleed screw, which is then opened. The user returns to the driver's seat, depresses the brake pedal with a smooth, steady stroke, and stowty releases it; this is repeated until the expelled fluid is clear of air bubbles. 23 Note that these kits simplify work so much that It is easy lo forget the master cylinder reservoir fluid level; ensure that this Is maintained at least above the MIN level line at all times.
Bleeding -using a pressure-bleeding kit 24 These kits are usually operated by the reservoir of pressurised air contained in the spare tyre. However, note that it will probably be necessary to reduce the pressure lo a lower level than normal; refer to the instructions supplied with the kit. 2$ By connecting a pressurised, fluid-filled container to the master cylinder reservoir, bleeding can be carried out simply by opening each screw In turn (in the specified sequence), and allowing the fluid to flow out until no more air bubbles can be seen in the expelled fluid. 28 This method has the advantage that the large reservoir of fluid provides an additional safeguard against air being drawn into the system during bleeding. 27 Pressure-bleeding is particularly effective when bleeding 'difficult' systems, or when bleeding the complete system at the time of routine fluid renewal.
All methods 28 When bleeding is complete, and firm pedal feel is restored, wash off any split fluid, lighten the bleed screws securely, and refit their dust caps (where applicable). 29 Check the hydraulic fluid level in the master cylinder reservoir, and top-up if necessary. 30 Discard any hydraulic fluid thai has been Wed from the system; it will not be fit for re-use. 91 Check the feel of the brake pedal. If it feels at all spongy, air must still be present in Vie system, and further bleeding is required. Failure to bleed satisfactorily after a reasonable repetition of the bleeding procedure may be due to worn master cylinder seals.
12 Master cylinder- % removal
and
refitting SK
A
Warning: 8efore starting work, refer to the warning at the beginning of Section 11 concerning the dangers of hydraulic fluid.
Removal 1 Remove the master cylinder fluid reservoir cap, and syphon the hydraulic fluid from the reservoir. Note: Do not syphon the fluid by mouth, as It Is poisonous; use a syringe or an old poultry baster. Alternatively, open any convenient bleed screw In the system, and gently pump the brake pedal to expel (he fluid through a tube connected to the screw (see Section 11). Disconnect the wiring connector from the brake fiuld level sender unit. 2 Carefully prise the fiuld reservoir from the seals and release it from the top of the master cylinder. 3 Wipe clean Ihe area around the brake pipe unions on the side of the master cylinder, and place absorbent rags beneath the pipe unions to catch any surplus fluid. Make a note of the correct fitted positions of the unions, then unscrew the union nuts and carefully withdraw the pipes. Plug or tape over the pipe ends and master cylinder orifices, to minimise the loss of brake fluid, and to prevent the entry of dirt into the system. Wash off any spilt fluid immediately with cold wafer.
A 22.45 to 22.65 mm
Cut the finger tips from an old rubber glove end secure them over the open ends of the brake pipes with elastic bands • this wifi heip to minimise fluid lots and prevent the Ingress of contaminants.
4 Slacken and remove the nuts securing the master cylinder to the vacuum servo unit, then withdraw the unit from the engine compartment. 5 Where applicable, recover the seals from the rear of the master cylinder, and discard them; new items must be used on refitting. 8 With the master cylinder removed, check that the distance between the end of the vacuum servo unit pushrod and the master cylinder mating surface is as shown in the diagram. If necessary, the distance may be adjusted by turning the nut at the end of the servo unit pushrod (see illustration).
Refitting 7 Fit new rubber seals and then press the fluid reservoir into the ports at the top of the master cylinder 8 Remove all traces of dirt from the master cylinder and servo unit mating surfaces, and where applicable, fit a new seal between the master cylinder body and the servo. 9 Fit the master cylinder to the servo unit, ensuring that the servo unit pushrod enters the master cylinder bore centrally. Refit the
B Adjustment nut
Page 190 of 225
Suspension and steering 10*2
Torque wrench settings (continued) Nm ibt ft Rasr suspension Damper lower securing bolt 95 70 Damper upper securing bolt 60 44 Handbrake cable support bracket-to-trailing arm screws 15 11 Hub nut 280 207 Trailing arm securing bolt 150 111 Steering Ignition switch/steering column lock securing bolts 4 3 Steering column mounting bolts 55 41 Steering gear mounting bolts 70 52 Steering wheel nut' 50 37 Subframe-to-body bolts 110 81 Track-rod end to hub carrier 40 30 Unlversaijointclampbolts 20 15 Roadwheels Roadwheel bolts 85 63 * Use a new nut
1 General information
Front suspension The front suspension is independent, comprising transverse lower wishbones, coil spring-over-damper strut units and an anti-roll bar. The hub carriors are bolted to the base of the stmt units and are linked to the lower arms by means ot balliotnts. The entire front suspension assembly is mounted on a subframe, which is In turn botted to the vehicle body.
Rear suspension The rear suspension incorporates a torsion beam axle, trailing arms, coil springs and separate telescopic dampers. In addition, a rear anil-roll bar is fitted to certain models. The components form a discrete sub-assembly which can be unboiled from the underside of the vehicle separately or as a complete unit.
Steering The two-piece steering shaft runs in a tubular column assembly, which is bolted to a bracket mounted on the vehicles bulkhead. The shaft Is articulated at its lower end by means of a universal Joint, which is clamped to the steering shaft and the steering gear pinion by moans of clamp bolts. The steering gear is mounted on the engine compartment bulkhead, and is connected to the steering arms projecting rearwards from Ihe hub carriers. The track-rods are fitted with balljoints at their inner and outer ends, to allow for suspension movement, and are threaded to facilitate ad|ustment. Hydrauiically-assisted power steering ts fittod to some models. The hydraulic system is powered by a belt-driven servo pump, which is driven from the crankshaft pulley.
Certain models are fitted with an airbag system. Sensors built into the vehicle body are triggered in the event of a front end collision and prompt an Electronic Control Unll (ECU) to activate the airbag, mounted In the centre of the steering wheel and the facia. This reduces the risk of the front seat occupants striking the steering wheel, windscreen or facia during an accident.
A
Warning: For safety reasons, owners are strongty advised to entrust to an authorised Flat dealer any work which involves disturbing the airbag 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 that the airbag system Is fully operational following reassembly.
2 Front hub bearings -renewal *
Note: A balljoint separator tool, and a press or suitable alternative tools (see text) will be required for this operation. The bearing will be destroyed during the removal procedure.
Removal 1 Chock the rear wheels, apply the handbrake, then jack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). Remove the appropriate roadwheel. 2 Remove the brake disc and caliper, with reference to Chapter 9. Note that the caliper body can remain bolted to its bracket: there is no need lo disconnect the brake fluid hose from the caliper. 3 With reference to Chapter 8. slacken and remove the driveshaft hub nut. 4 On models with ABS, unbolt the ABS wheel sensor, and remove the screw securing the
ABS sensor wiring to the hub carrier. Suspend the sensor away from the working ares, to avoid the possibility of damage. 5 With reference to Section 17, separate
th»
track-rod end from the hub carrier, using
a
suitable balljoint splitter. 6 Remove the two nuts from tho botts securing Ihe hub carrier to the base of th» suspension strut (refer to Section
3).
Withdrew the bolts and separate the top of hub earrtt from the strut. 7 Disconnect the outboard end of Ito driveshaft from the hub, as described durirg the driveshaft removal and refitting procedm in Chapter 8. Note: There is no naod fo disconnect the Inboard end of the
drivestett
from the transmission. Caution: Do not allow the end of tin driveshaft to hang down under its
own
weight, as this places strain on the
CV
joints; support the end of the shaft uskg wire or string. 8 Slacken and remove the nut and clamp bolt, then push the lower arm down anc separate the balljoint from the base of the tab carrier (see illustrations). 9 At this stage, it is recommended that
the bub
carrier be taken to a engineering workshop,
as
the hub and bearing should ideally be removed from the hub carrier using a hydraulic press
2.8a ... Slacken and remove the nut...
Page 191 of 225
Suspension and steering 10*3
2.10 Using a slide hammer to extract the hub 2.11 Wheel bearing components / Hub carrier 2 Wheel bearing 3 Circlip
Owners wishing to attempt the work them-
selves
should proceed as follows. 10 Mount tho hub carrier firmly In a bench vice. Attach a slide hammer to the hub flange and extract the hub. together with the inner bearing race, If it has remained attached to the hub. Unbolt and remove the heat shield
(see
Illustration). 11 Mount the hub carrier horizontally in the rice, then remove tho bearing retaining circlip. Using a suitable length of tubing as a drift, drive Ihe bearing outer race from the carrier (see Illustration). Note that a flange on the outboard side of the carrier means that the bearing can only be driven out in one direction. 12 Support the inner bearing race, if it has remained attached to the hub, then press or drive the hub from the race. Alternatively, pull trie bearing race from the hub using a suitable Iw or three-legged puller. 13 Before Installing the new bearing, thoroughly clean the bearing location in the tub carrier. U Fit the new bearing from the Inboard side the hub: press or drive the bearing into position, applying pressure only to the bearing oiler race. Oo not lubricate the mating surface
ol the
bearing In an attempt to ease installation. 15 Fit the bearing retaining circlip to its 700ve in the hub carrier, then refit the heat
shield and tighten the retaining screw securely. 16 Support the outer face of the hub carrier across the jaws of a bench vice. 17 Carefully press or draw the hub into the bearing, noting that the bearing inner race must be supported during Ihis operation, to prevent It from being separated from the outer race. This can be achieved using a suitable socket, threaded rod, washers and a length of bar (see Illustration). 18 On completion, check that the hub rotates freely in the hub carrier without resistance or roughness.
2.17 Typical method of drawing the hub into the wheel bearing using improvised tools
Refitting 19 Reconnect the outboard end of the drive-shaft to the hub as described In Chapter 8. Ensure that the driveshaft nut is tightened to the correct torque and adequately staked. Ideally, for safety reasons due to the very high torque of the driveshaft nut, carry out final tightening and staking of the nut after refitting the roadwheel and lowering the car to the ground. 20 Reconnect the hub carrier to the lower arm balljoint, then fit a new clamp bolt nut. Tighten tho nut to the specified torque. 21 Engage the hub carrier with the suspension strut, then refit the securing bolts and nuts, tightening them to the specified torque. 22 Reconnect the steering track-rod balljoint to the hub carrier steering arm. Use a new nut and tighten it to the specified torque. 23 Refer to Chapter 9 and refit the brake disc and caliper. 24 Where applicable, fit the ABS wheel sensor into its mounting hole and tighten the securing screw. 25 Refit the roadwheel, and tower the vehicle to the ground. 26 Have the front wheel alignment checked by a Fiat dealer or a tyre specialist at the earliest opportunity.