2C*2 Diesel engine in-car repair procedures
Refitting 6 Locate a new gasket on the cylinder head and make sure tt Is correctly seated. 7 Lower the cover onto the gasket making sure the gasket Is not displaced, 8 Insert the mounting bolts and tighten them securely In a progressive sequence. Position Ihe support brackets as noted during removal. 9 Clip ihe coolant hoses in position then refil the air ducting.
7 Camshaft oil seal -renewal
8 Crankshaft oil seals -renswal I
9 Cylinder head -
removal
and refitting
1 Remove the timing belt and camshaft sprocket as descnbed in Sections 4 and 5. 2 Using a suitable hooked instrument, remove tho oil seal from the cylinder head taking care nol to damage the surface of the camshafl. Alternatively drill a small hole In tho oil seal and Insert a self-topping screw - the seal can then be removed by pulling on the screw with a pair of pliers. 3 Clean the seating In the cylinder head and tho end of the camshaft To prevent damage to the new oil seal as It is being fitted, wrap some adhesive tape around the end ol the camshaft and lightJy oil it. 4 Dip tho new ail s«al In oil then locate it over Ihe camshaft making sure that the sealing lips are facing inwards. 5 Using a suitable tubular drift, drive the oil seal squarely into the cylinder h*ad. Remove the adhesive tap© 6 Refit the camshaft sprocket and timing belt with reference to Sections 6 and 4.
Front (right-hand side) oil seal t The front oil seal is located in the oil pump casing on the front of the crankshaft. Remove the timing belt as described in Section 4 and the crankshaft sprocket as described in Section 5, 2 Using a suitable hooked instrument, remove the oil seal from the oil pump casing taking care not to damage the surface of the crankshaft. Alternatively drill a small hole In the oil soal and insert a self-tapping screw - the seal can then be removed by pulling on the screw with a pair of pliers. 3 Clean the seating in the oH pump and the surface of the crankshaft. To prevent damage to the new off seal as It Is being fitted, wrap some adhesive tape around the end of tha crankshaft and lightly oil it. 4 Oip the new oii seal In oil then otter it up to the oil pump casing making sure that the sealing Hps are facing inwards,
8.Ba Rear oil soal and housing
5 Using a suitable tubular drift, driva the oil sea! squarely into the casing. Remove the adhesive tape. 6 Refit the crankshaft sprocket and timing belt with reference to Sections 5 and 4.
Rear (left-hand side) oil seal Note: The following paragraphs describe renewal of the rear oil seal leaving the housing In position. The alternative mathod is to remove the housing and renew the oil seel on the bench, however there is then the possibility of damaging the sump gasket. Refer to Chapter 2D for details of removing the mar oil sea! housing. 7 Ramove the flywheel as described in Section 10. 8 Using a suitable hooked Instrument. remove 1he oil seat from the roar oil seal housing taking care not to damage Ihe surface of Ihe crankshaft. Alternatively dnll a small hole In the o» seal and insert a self-tapping screw - the seal can ihan be removed by pulling on the screw with a pair of pliers (see Illustrations), 9 Clean the seating in the housing and the surface of the crankshaft. Check the crankshaft for burrs which may damage the oil seal tip of tno new saal, and It necessary use a Una file to removothem. 10 Dip the new soal in clean engine oil and carefully tocato it over tho crankshafl rear Range making sure that
H
the correct way round. 11 Progressively tap the oH seal into the housing keepfng it square to prevent distortion. A block of wood is useful for this purpose. 12 Refit the flywheel with reference to Section 10.
I
5.8b Using a self-tapping screw and pliers to remove the rear oil seal
Removal Note: The cylinder head bolts are of special splined design and a Fiat tool should be obtained to unscrew them. A Torn key will
not
fit however In practise It was found that a close-fitting Allen key could bo used as an alternative. 1 Disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual), 2 Remove tha battery as described In Chapter 5A. 3 Refer to Chapter IB and carry out the following: o) Drain the engine oil, b) Drain the cooling system. 4 Remove the timing belt as described in Section 4. 5 Unbolt and remova the relay guard and bracket from the left-hand side of the engine. 6 Unbolt and remove the battery mounting tray and disconnect the wiring and lines from the modulator valva and relays. 7 Remove the air eleanar assembly and air duct with reference lo Chapter 4C. 8 Loosen the clip and disconnect the vacuum hosa from the vacuum pump on the left-hand end of the cylinder head. 9 Loosen Ihe clips and disconnect the radiator top hose from the cylinder head outlet. Also disconnect the heater inlet hose from the thermostat housing, 10 Loosen the clips and disconnect the expansion tank and heater outlet hoses. 11 Identify all wiring connectors then disconnect them from the cylinder head, 12 Unscrew the expansion tank mounting screws, then disconnect tha expansion tank hoses at their connections to the engine. Remove the expansion tank from tha engine compartment. 13 Release tha clip and disconnect ihe crankcase breather from the left-hand rear of the cylinder head. 14 Unbolt the power steering pump uppar cover bracket then unscrew the pivot ana adjustment bolts while leaving ihe tMd lioses still attached. Release the drivebelt (if still In place) then tie the pump to the bulkhead. 15 Loosen tha clips and disconnect Ihe short coolant hose from the cylinder head outlet to the coolant pump (soe illustration). 18 At the rear of the engine, unbolt and disconnect the oil delivery pipe from the turbocharger (where applicable) and crankcase (see Illustrations). 17 Disconnect the return hose from tha thermostat housing to the coolant pump (see Illustration), 18 Unbolt the metal coolant return pipe and pull it out from the coolant pump inlet elbow (see Illustrations).
expert22 flna http://rutracker.org
2D*10 Engine removal and overhaul procedures
Engine and transmission -removal, separation, connection and refitting
Note: The engine Is lowered from the engine compartment as a complete unit with the transmission; tho two are then separated for overhaul.
Removal 1 Remove the bonnet and disconnect the washer tubing as described in Chapter 11 (see illustrations). 2 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. In order to remove tne engine/transmission assembly in an upright position from under the vehicle, there must be a minimum clearance of 660 mm between the floor and the front crossmember. Additional height Is necessary if the assembly is to be lowered onto a trolley. 3 Where fitted, unbolt and remove the engine compartment lower cover. 4 Remove the auxiliary drivebelt(s) with reference to Chapter 1A or 1B. 5 Dram the engine oil. transmission oil/fluid and coolant with reference to Chapter 1A or 1B. 6 Remove the battery (see Chapter 5A). 7 On manual transmission models with a cable dutch, disconnect the clutch cable from the transmission (refer to Chapter 6). On manual transmission models with a hydraulic clutch unbolt the clutch slave cylinder from the top of the transmission then fit a cable-tie around it to prevent the piston coming out (see Illustration). Position the cylinder to one side. 8 Unscrew the nut and disconnect the earth lead from the transmission (see illustration). Petrol engines 9 Unbolt and remove the battery tray. 10 Disconnect the wiring from the reversing light switch. 11 On manual transmission models disconnect the reverse Inhibition cable from the transmission then disconnect the gear selector rod from the lever on the transmission. 12 Remove the air cleaner and ducting as descnbed In Chapter 4A or 4B. 13 On automatic transmission models disconnect the kickdown cable and gear selector cable as described in Chapter 7B. Also disconnect the wiring for the electro-magnetic clutch. 14 Unbolt and remove the cover from the bulkhead then disconnect the oxygen sensor wiring. 15 Disconnect the remaining wiring at the bulkhead and release the fuse holders at the mounting. 16 Disconnect the vacuum pipe from the inlet manifold, and also disconnect the wiring connector located next to it.
4.1a Unscrewing the bonnet hinge bolts
17 Unscrewthenutsandseparatetheengine wiring harness lead from the battery positive cable terminal. 18 Disconnect the accelerator cable from the engine as described in Chapter 4A or 4B, 19 Loosen the clip and disconnect the radiator top hose from the elbow on the left-hand end of the cylinder head. Similarly disconnect the bottom hose. On 16-valve models, remove the radiator electric cooling fan as described in Chapter 3. 20 Identify the hoses connected to the throttle housing, then disconnect them. 21 Identify the coolant heater hoses on the bulkhead for position, then loosen the clips and disconnect the hoses. 22 Loosen the clip and disconnect the brake servo vacuum hose from the Inlet manifold. Where applicable, disconnect the remaining emission control system vacuum hoses from the Inlet manifold after Identifying their locations to aid refitting. 23 Disconnect tho fuel supply and return hoses from the throttle housing. 24 Release the connector from the ignition/fuel ECU located on the right-hand side of the engine compartment. 25 Unscrew the nut and detach the earth cable from its location near the ECU. 26 Disconnect the diagnostic connector located near the ECU. 27 On models fitted with power steering, refer to Chapter 10 and unbolt the power steering pump from the front of the engine without disconnecting the hydraulic fluid lines then tie It to one side so that it will not obstruct the removal of the engine. On
4.1b Disconnecting the washer tubing
models with air conditioning, similarly unbolt the air conditioning compressor and position it clear of the engine. Do not disconnect the air conditioning refngerant pipes/hoses. 26 On manual transmission models pull out the retaining plate and disconnect the gear selector cable from the lever on the transmission. 29 Unscrew the nuts retaining the track rod ends on the swivel hubs and use a balljoint separator tool to disconnect them. 30 Release the flexible brake fluid hoses and ABS system sensor wrring from the front suspension struts. 31 On manual transmission models, unscrew the nuts from the outer ends of each driveshaft. To prevent the hubs from turning either have an assistant depress the brake pedal, or temporarily Insert two wheel bolts and use a lever to hold the hub. 32 On automatic transmission models use a suitable drift to drive out Ihe roll pins securing 2D the inner ends of the drlveshafts to tho trans-mission output stubs. Turn the driveshalts as necossary to access the roll pins . 33 Unscrew the two bolts securing the right-hand swivel hub assembly to the front suspension strut, then move the hub assembly outwards. On manual transmission models release the outer end of the driveshaft from the hub assembly - on automatic transmission models slide the inner end of the driveshaft off the final drive output stub. Take care not to strain the flexible brake hose while doing this. Move the driveshaft to one side thon temporanly refit the hub assembly to the strut. On manual transmission models, make
^ - / //
4.7 Fit a cable tie around the dutch slave cylinder to prevent the piston coming out 4.8 Disconnecting the earth lead from the transmission
2D*10 Engine removal and overhaul procedures
05 Remove the brush holder assembly from the automatic transmission as described in Chapter 7B, Section 4. The brushes bear on the slip rings at the rear of the electro-magnetic clutch housing and they may be damaged when the transmission is removed. 86 Unscrew and remove the transmission-to-engine bolts then carefully draw the transmission away from the engine, resting It securely on wooden blocks. Collect the locating dowels If they are loose enough to be extracted, 87 If the oil pump driveshaft remains engaged with the crankshaft, remove it and reert Into the transmission to protect It from damage.
Connection 86 If the engine and transmission have not been separated, go to paragraph 104. Manual transmission models 89 Smear a little high-melting-point grease
on
the splines of the transmission input shaft. Do not use an excessive amount as there Is the risk of contaminating the clutch friction plate. 90 Carefully offer up the transmission to the engine cylinder block, guiding the input shaft through the clutch friction plate. 91 Refit the transmission-to-engine bolts and
the
single nut. hand^jghtenlng 1hem to secure the transmission in position. Note: Do not hghten them to force the engine and transmission together. Ensure that the beilhousing and cylinder block mating faces will butt together evenly without obstruction, before finally tightening the bolts and nut securely. Automatic transmission models 92 Check that the oil pump driveshaft is correctly engaged with the oil pump in the transmission. 93 Carefully offer up the transmission to Ihe rear of the engine and insert the oil pump driveshaft In the centre of the electro-magnetic clutch housing. Locate the transmission on the locating dowels then Insert the bolts and tighten them securely. 94 Refit the brush holder assembly to the automatic transmission with reference to Chapter 7B, Section 4. Petrol engines 96 Refit the transmission lower cover and tighten the bolts. 96 Locate the support bracket on the lower cover, then insert the bolts hand-tight. Also Insert the bolts securing the bracket lo the rear of Ihe cylinder block. With all the bolts Inserted, tighten them securely. 97 Refit the earth leads and tighten the bolts. Diesel engines 98 Refit the rpm sensor and tighten the bolts. 99 Insert the Intermediate shaft through the bracket then locate the dust boot on it and insert the Inner end in the transmission.
100 Refit and tighten the bolts securing the Intermediate shaft to the bracket on the rear of the cylinder block. 101 Refit the transmission lower cover and tighten the bolts. Ail models 102 Refit the starter motor (see Chapter 5A). 103 Refit the wiring harness to the components on the engine/transmission assembly making sure it is routed correctly.
Refitting 104 Locate the engine/transmission assembly beneath the engine compartment and attach the hoist to the lifting eyes. 105 Carefully lift the assembly up into the engine compartment taking care not to damage the surrounding components. 106 Reconnect the left-hand engine/trans-mission mounting to the body and tighten the bolts. 107 Reconnect Ihe right-hand engine mounting to the body and tighten the bolts. 108 Working beneath the vehicle, refit the rear engine mounting and tighten the bolts. 109 Disconnect the hoist from the engine and transmission lifting eyes and remove the hoist from under the vehicle. 110 The remainder of the refitting procedure is the direct reverse of the removal procedure, noting the following points:
a) Ensure that alf sections of the wiring harness follow their original routing; use new cable-ties to secure the harness In position, keeping it away from sources
of
heat and abrasion. b) On vehicles with manual transmission check and if necessary adjust the gearchenge cable and rod with reference to Chapter 7A. c) On vehicles with automatic transmission use new ro//p/ns fo secure the driveshafts to the transmission output stubs. Also check and if necessary adjust the kickdown end selector cables with reference to Chapter 78. d) Ensure that afi hoses are correctly routed and are secured with the correct hose clips, where applicable. If the hose clips cannot be used again; proprietary worm drive clips should be fitted
In
their place. e) Refill the cooling system as described in Chapter 1A or 18. f) Refill the engine with appropriate grades and quantities of oil (Chapter
1A
or 1B). g) Refit and adjust the auxiliary drivebelt(s) wfth reference fo Chapter 1A or 1B. h) Check and If necessary adjust the accelerator cable with reference to Chapter
AA,
48 or
AC.
i) When the engine is started for the first time, check for
air,
coolant, lubricant and fuel leaks from manifolds, hoses etc. If
the
engine has been overhauled, read
the
notes In Section 13 before attempting to starlit.
5 Engine overhaul • dismantling sequence
1 It is much easier to dismantle and work on the engine if it is mounted on a portable engine stand. These stands can often be hired from a tool hire shop. Before the engine is mounted on a stand, the flywheel should be removed, so that the stand bolts can be tightened Into the end of the cylinder block/crankcase. 2 If a stand Is not available, it Is possible to dismantle the engine with it blocked up on a sturdy workbench, or on the floor, Be very careful not to tip or drop the engine when working without a stand. 3 If you intend to obtain a reconditioned engine, all anclllarles must be removed first, to be transferred to the replacement engine (just as they will If you are doing a complete engine overhaul yourself). These components Include the following:
Petroi engines a) Power steering pump if removed with the engine (Chapter
10).
b) Alternator fmcluding mounting brackets) and starter motor (Chapter
SA).
c) The Ignition system and HT components including ail sensors, HT leads and
spark
plugs (Chapters 1A and
SB).
d) The fuel injection system components (Chapters A A and
AB).
e) All electrical switches, actuators and sensors, and the engine wiring harness (Chapters 4A, AB, SB). f) Inlet and exhaust manifolds (Chapters 4A, AB end
AD).
g) Engine oil dipstick and tube. h) Engine mountings (Chapter
2A).
i) Flywheef/driveptate (Chapter
2A).
j) Clutch components (Chapter
6)
- manual transmission. k) Electro-magnetic clutch components (Chapter 7B) - automatic transmission. I) Cooling system components (Chapter
3).
Diesei engines a) Power steering pump //removed with the engine (Chapter
10).
b) Alternator (Including mounting brackets) and starter motor (Chapter 5A). c) The glow plugfpre-heatlng system components (Chapter
SC).
d) Ait fuel system components, including the fuel injection pump, all sensors and actuators (Chapter
AC).
e) The vacuum pump. f) Ail electrical switches, actuators and sensors, and the engine wiring harness (Chapter 4C and 5C). g) Inlet and exhaust manifolds and, where applicable, the turbocharger (Chapter
AC
and 4D). h) The engine oil level dipstick and its tube. i) Engine mountings (Chapter
2C).
6*1
Chapter 6
Clutch
Contents
Clutch - adjustment Clutch assembly - removal, inspection and refitting Clutch cable • removal and refitting Clutch hydraulic system - bleeding
Degrees of difficulty
2 Clutch master cylinder • removal and refitting 5 7 Clutch release mechanism - removal, Inspection and refitting 8 3 Clutch slave cylinder - removal and refitting 6 4 General information 1
Easy, suitable for
novice with little experience oi^
Faidy easy,
suitable for beginner
with
^
some
experience
Fairly difficult, suitable
for
competent ^
DIY
mechanic ^
Difficiit, suitable for ^ experienced DIY JR mechanic ^
V<*y difficult,
jk
suitable
for expert
DIY
« or professional ^
Specifications
General Type
Clutch pedal travel (cable-operated mechanism)
Friction plate diameter 8-valve petrol engines 16-valve petrol engines Diesel engines
Torque wrench setting Pressure plate retaining bolts
Single dry plate with diaphragm spring, cable- or hydraullcally-operated according to model 140.0 ± 5.0 mm
181.5 mm 190.0 mm 200.0 mm
Nm Ibf ft 16 12
1 General information
Vehicles with manual transmission are fitted with a pedal operated single dry plate clutch system. When the clutch pedal is depressed, effort is transmitted to the clutch release mechanism either mechanically by means of a cable, or hydraullcally by means of a master
2.5 Clutch cable adjustment
cylinder and slave cylinder. The release mechanism transfers effort to Ihe pressure plate diaphragm spring, which withdraws the pressure plate from the flywheel and releases the driven plate-Where applicable, the hydraulic fluid employed in the clutch system is the same as that used in the braking system, hence fluid is supplied to the master cylinder from a tapping on the brake fluid reservoir. The clutch hydraulic system must be sealed before work Is carried out on any of its components and then on completion, topped up and bled to remove any air bubbles.
2 Clutch - % adjustment §§ ^
Note: This procedure applies to models fitted with a cable-operated dutch
release
mechanism. No adjustment is possible on models with the hydrauHcaSy-operated system. 1 The clutch adjustment Is checked by measuring the clutch pedal travel. If a new cable has been fitted, settle it in position by depressing the clutch pedal at least thirty times. 2 Ensure that there are no obstructions
beneath the clutch pedal then measure the distance from the centre of the clutch pedal pad to the base of the steering wheel with the pedal In the at-rest position. Depress the clutch pedal fully to the floor, and measure the distance from the centre of the clutch pedal pad to the bata of the steering wheel. 3 Subtract the first measurement from the second to obtain the clutch pedal travel. If this is not with the range given in the Specifications at the start of this Chapter, adjust the clutch as follows. 4 The clutch cable Is adjusted by means of the adjuster nut on the transmission end of the cable. Access to the nut is from under the vehicle. Apply the handbrake then jack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). 5 Working under the left-hand side of the engine compartment, slacken the locknut from the end of the clutch cable. Adjust the position of the adjuster nut. then depress the clutch pedal ten times and re-measure the dutch pedal travel. Repeat this procedure until the clutch pedal travel is as specified (see illustration). 6 Once the adjuster nut Is correctly positioned, and the pedal travel Is correctly set, securely tighten the cable locknut then lower the vehicle to the ground.
6*172
Chapter 8
Driveshafts
Contents
Oriveshaft gaiter check See Chapter 1A or 1B General information 1 Oriveshaft overhaul and rubber gaiter renewal 3 intermediate driveshaft - removal and refitting 4 Driveshafts - removal and refitting 2
Degrees of difficulty
Easy,
suitable for ^ novtoewithittle experience ^
Fatly
easy,
suitable for beginner with
some experience
^
Fairty
difficult, suitable
tor
competent OtYmechanlc
Difficult,
suitable for experienced DIY mechanic ^
Veiydfficult, ^
suitable
for
expert DIY
or professional ^
Specifications
General Type
Lubrication lubricant type
Torque wrench settings Driveshaft nut* All models except turbo diesel (M22 plain) Turbo diesel (M24 with staking and captive washer) Roadwheel bolts Suspension strut-to-hub carrier bolts Track-rod balljolnt-to-hub carrier 'Use a new nut.
Unequal-length, solid steel shafts, splined to Inner and outer constant velocity joints. Intermediate shaft with support bearing on turbo diesel models with equal length driveshafts.
Fiat specification grease, supplied with gaiter repair kit
Nm Ibfft
240 177 280 207 85 63 70 52 40 30
1 General information
Power is transmitted from the differential to
Ihe
roadwheels by the driveshafts. via inboard and outboard constant velocity (CV) joints (we illustrations). An intermediate drive shaft, with its own support bearing is fitted between the gearbox output and right-hand drive shafts on turbo desei models (see Illustration overleaf). This layout has the effect of equalising driveshaft angles at sll suspension positions and reduces tfveshaft flexing, which improves directional stability, particularly under acceleration. The outer Rzeppa type CV joints allow smooth transmission of drive to the wheels at all steering and suspension angles. Drive Is transmitted by means of a number of radially static steel balls that run In grooves between
the two halves of the joint. The type of inboard CV joint fitted is model dependant. Those fitted to all except the turbo diesel models are of the plunge-cup type; drive is transmitted across the joint by means of three rollers, mounted on the driveshaft in a tripod arrangement, that are radially static but are free to slide in the grooved plunge cup.
The inboard CV joints fitted to turbo diesel models are of the Rzeppa type, similar to those at the outboard end of the driveshaft. On the right-hand driveshafl, the joint is bolted directly to the end of the intermediate driveshaft flange. On the left-hand driveshaft, the joint is bolted to the transmission output shaft flange.
1.1a Cross section of driveshaft - petrol and non-turbo diesel models A Transmission side B Roadwheef side
9*2 Braking system
2.3a Release tho locking clip ...
1 General information
The braking system is of the vacuum servo-assisted. dual-circuit hydraulic type. The arrangement of Ihe hydraulic system is such that each circuit operates one front ond ono rear brake from a tandem master cylinder. Under normal circumstances, both circuits operate In unison However, in the event of hydraulic failure in one circuit, lull braking force will still be available at two diagonally-opposite wheels. All models covered in this manual are fitted with front disc brakes and rear drum brakes. The front disc brakes are aotuated by single-piston sliding lype calipers, which ensure lhat equal pressure is applied to each brake pad. The rear drum brakes incorporate leading and trailing shoes, which are actuated by twin-piston wheel cylinders. A self-adjust mechanism is incorporated, to automatically compensate for brako shoe wear. As the brake shoe linings wear, the footbrnke operation automatically operates the adjuster mechanism, which effectively lengthens the shoe strut and repositions the brake shoes, to remove the llning-to-drum clearance. The mechanical handbrake linkage operates the brake shoos via a lever attached to the trailing brake shoe.
2.3b ... and remove the pad wear indicator wiring and brake fluid line from the suspension strut Load sensitive proportioning valves operate on the rear brake hydraulic circuits, to prevent the possibility of the rear wheels locking before the front wheels under heavy braking. Note: When servicing any part of the system, work carefully and methodically; also observe scmpulous cleanliness when overhauling any part of the hydraulic sysiem. Always renew components (in axle sets, where applicable) if In doubt about their condition, and use only genuine Fiat replacement parts, or at least those of known good quality. Note the warnings given in Safety first and at relevant points in this Chapter concerning fhe dangers of asoestos dust and hydraulic fluid.
Models with anti-lock braking system (ABS) Available as an option on certain models, the anti-lock braking system prevents skidding which not only optimises stopping distances but allows full steering control to be maintained under maximum braking. By electronically monitoring the speed of each roadwheel in relation to the other wneete, Ihe system can detect when a wheel is about to lock-up, before control is actually lost. The brake fluid pressure applied to that wheel's brake caliper is then decreased and restored (or modulated) several times a second until control
£s
regained. The system components comprise an Electronic Control Unit (ECU), four wheel speed sensors, a hydraulic unit, brake lines and dashboard mounted warning lamps.
The hydraulic unit incorporates a tandem master cylinder, a valve block which modulates the pressure in the brake hydrauli: circuits during ABS operation, an accumulator which provides a supply of highly pressursed brake fluid, a hydraulic pump to charge Ihe accumulator and an integral electronic control unit (ECU). The four wheel sensors are mounted on the wheel hubs. The ECU uses the signals produced by the sensors to calculate Ihe rotational speed of each wheel, The ECU has a self-diagnostic capability and will inhibit the operation of the ABS il a fault is detected, lighting the dashboard mounted warning lamp. The braking system will then revert lo conventional. non-ABS operation. II the nature of the laull ie not immediately obvious upon inspection, the vehicle must be taken to a Fiat dealer, who will have the diagnostic equipment
required
lo interrogate the ABS ECU electronically and pin-point the problem
2 Front brake pads - & renewal S
A
Warning: Renew BOTH sets ol front brake pads at the same
time
- NEVER renew the pads on
only
one wheel, as uneven braking may result
A
Warning: Note that the dust created by wear of the pads
may
contain asbestos, which is a health hazard. Never blow It out with compressed air, and don't inhale any of
it.
An approved filtering mask should be worn when working on the brakes. DO NOT use petrol or petroleum-based solvents to clean brake parts; use proprietary braks cleaner or methylated spirit only. 1 Firmly apply the handbrake, then jack up the front of the car and support it securely
on
axle stands (see Jacking and vehicle supporti. Remove the front roadwheeis. 2 Wording on one side of the vehicle, puth the caliper piston into its bore by pulling the caliper outwards. If necessary, press the piston back into its bore using a large G-clamp or a piston retraction tool. Keep a careful eye on the level of brake llufd in Ihe I reservoir as you do this - ensure that the
level
I does not rise above the MAX marking. 3 Whore applicable, release the locking dp and remove the pad wear indicator
wiring end
brake fluid line from the bracket at Ihe
base of
the suspension strut (see illustrations).
Petrol models without ABS 4 Remove the locking clip and exlracl the lower guide pin from the caliper (see illustrations) 5 Pivot the caliper body upwards and support In position with a length of wire or a cabie-fc. Avoid straining the hydraulic hose.
2,4a Remove the locking clip ... 2.4b ... and extract the lower guide pin from the caliper (petrol models without ABS)
Braking system 9®3
2.6a Unscrew the upper...
Petrol models with ABS and diesel models 6 Unscrew the upper and lower caliper guide cin bolts, using a slim open-ended spanner to counterhold the head of the guide pin (see illustrations). Discard the guide pin bolts -new items must be fitted on reassembly. 7 Lift the caliper from the hub/disc assembly (see illustration). Suspend it from a suitable point on the suspension using a length of wire or 8 cable-tie, to avoid straining the hydraulic hose.
All models Caution: Do not depress the brake pedal until the caliper is refitted, or the piston will
be
pushed out of Its bore. 8 Withdraw the brake pads from the caliper bracket (see illustrations). 9 Measure the thickness of each brake pad's foclion material. If either pad is worn at any point to the specified minimum thickness or less, all four pads must be renewed. Also, the pads should be renewed if any are fouled with oil or grease; there is no satisfactory way of degreasing friction material, once contaminated. If any of the brake pads are worn unevenly, or are fouled with oil or grease, trace and rectify the cause before reassembly.
A
Warning: Do not be tempted to swap brake pads over to compensate for uneven wear. 10 if the brake pads are still serviceable, carefully clean them using a clean, fine wire brush or similar and brake cleaning fluid. Pay particular attention to the sides and back of the metal backing. Where applicable, clean out the grooves in the friction material, and pick out any large embedded panicles of dirt
or
debris. 11 Clean the surfaces of the brake pad contact points In the caliper body and caliper mounting bracket. 12 Prior to fitting the pads, check that the giide pins can slide freely in the caliper body, and check that the rubber guide pin gaiters
are
undamaged. Brush the dust and din from
the
caliper and piston, but do not inhale it. as
4 may
contain asbestos. 13 Inspect the dust seal and the area around Ihe piston for signs of damage, corrosion or
models with ABS and diesel models)
brake fluid leaks. If evident, refer to Section 3 and overhaul the caliper assembly. 14 If new brake pads are to be fitted, the caliper piston must be pushed back into the cylinder, to allow for the extra depth of the friction material. Either use a G-clamp or similar tool, or use suitable pieces of wood as levers. Provided that the master cylinder reservoir has not oeen overfilled with hydraulic fluid, there should be no spillage, but keep a careful watch on the fluid level while retracting the piston. If the fluid level rises above the MAX level line at any time, the surplus should be siphoned off. A Warning: Do not syphon the fluid by mouth, as it is poisonous; use a syringe or an old poultry baster. 15 Apply a little high temperature brake grease to the contact surfaces of the pad backing plates: take great care not to allow any grease onto the pad friction linings. Similarly, apply brake grease to the pad contact points on the caliper bracket - again take care not to apply excess grease, which may contaminate the pads. 16 Place the brake pads in position on the caliper bracket, with the friction material facing the surfaces of the brake disc. Feed the wear indicator cable through the caliper body aperture.
Petrol models without ABS 17 Pivot the caliper body down over the brake pads, then refit the guide pin and clip.
2.7 Lift the caliper from the hub/disc assembly
Petrol models with ABS and diesel models 18 Fit the caliper body in position on the caliper bracket, then fit the new guide pin bolts and tighten them to the specified torque.
AH models 19 Check that the caliper body can slide freely on the guide pins. Ensure that the flexible hydraulic hose is not twisted or kinked In any way. Turn the steering from lock to lock and check that the hose does not chafe against the suspension or steering gear. 20 Where applicable, reconnect the pad wear indicator wiring and press it into the retaining clips on the suspension. 21 Repeat the above procedure on the remaining front caliper. 22 With both sets of front brake pads fitted, depress the brake pedal repeatedly until the pads are pressed into firm contact with the brake disc, and normal pedal pressure is restored. Any sponginess felt when depressing the pedal is most probably due to air trapped inside the hydraulic system - refer to Section 11 and bleed the braking system before progressing any further. 23 Refit the roadwheels. and lower the vehicle to the ground. 24 Check the hydraulic fluid level as described in Weekly checks. 25 Check the operation of the braking system thoroughly,
2.8a Withdraw the outboard... 2.8b ... and inboard brake pads from the caliper bracket
Braking system 9®5
2 Rotate the brake disc by hand and examine the whole of the surface area swept by the brake pads, on both sides ot the disc. Note: /( will bo necessary to remove the front brake pads to allow an adequate inspection of the disc's rear surface; refer to Section 2 tor details. 3 Typically, the disc surface will have a polished appearance and should be free from heavy scoring. Smooth rippling is produced by normal operation and does not indicate excessive wear. Deep scoring and cracks, however, are indications of more serious damage in need of correction. 4 If deep scoring Is discovered, it may be possible to have the disc reground to restore the surface, depending on the extent of the damage. To determine whether this is a feasible course of action, it will be necessary to measure the thickness of the disc, as described later. 5 Check the whole surface of the disc for cracks, particularly around the roadwheel bolt holes. A cracked disc mutt be renewed. 6 A ridge of rust and brake dust at the inner and outer edges of the disc, beyond the pad contact area is normal - this can be scraped tway quite easily. 7 Raised ridges caused by the brake pads eroding the disc material, however, are an indication of excessive wear. If close examination reveals such ridges, the oiicknoss of the disc must be measured, to usess whether it is still fit for use. 8 To measure the thickness of the disc, take readings at several points on the surface using a micrometer. In the area swept by the brake pads (see Illustration). Include any points where the disc has been scored: align me Jaws of the micrometer with the deepest ares of scoring, to get a true indication of the extent of the wear. Compare these ineasurements with the limits listed in the Specifications. If the disc has worn below its minimum thickness, at any point, it must be renewed. 9 If the discs are suspected of causing brake luddor, check the disc runout, using one of
me
following methods: Runout measurement -
DTI
gauge method 10 Refit the four roadwheel bolts, together
w.1h
one M14 plain washer per stud • this will ensure adequate disc to hub contact. Tighten te studs to 5 Nm (4 Ibf ft). 11 Clamp the DTI gauge to a stand and attach the stand, preferably via a magnetic oase. to the strut mounting bracket. Align the jauge so that its pointer rests upon the area of the dtsc swept by the brake pads, on an arc i mm from the outer edge of tho disc (soe illustration). 12 Zero the gauge and slowly rotate the disc trough one revolution, observing tho pointer rcovement. Note the maximum deflection recorded and compare the figure with that >«ted In Specifications.
4.8 Measuring brake disc thickness with a micrometer
Runout measurement -feeler blade method 13 Use the feeler blades to measure the clearance between the disc and a convenient fixed point, such as the disc backplate. Rotate the disc and measure the variation in clearance at several points around the disc, Compare the maximum figure with that listed in Specifications. 14 If the disc runout Is outside of its specified tolerance, first check that the hub Is not worn (see Steering and suspension check in Chapter 1A or 1B). If the hub is In good condition, remove the disc (as described later in this Section), rotate it through 180° and refit it. This may improve the seating and eradicate Ihe excessive runout. 15 If the runout is still unacceptable, then It may be possible to restore the disc by regrinding; consult your Fiat dealer or a machine shop for a professional opinion - it may prove more economical to purchase a new disc. If the disc cannot be reground, then it must be renewed.
Removal 16 Mark the relationship between the disc and the hub with chalk or a marker pen, to allow correct refitting. 17 To allow the disc to be removed, undo the two bolts securing (he brake caliper mounting bracket to the hub carrier (see illustration 3.7). Withdraw the brake caliper and mounting bracket assembly, complete with brake pads, from the hub carrier, and hang it from a rigid point on the suspension, using v/lre or a
4.18a Slacken and remove the disc locating studs ...
4.11 Brake disc runout measurement - DTI gauge method
cable-tie. Oo not allow it to dangle freely as this will strain the brake hose. 18 Slacken and remove the disc locating stud(s). Support the disc as you do this and lift it off as it becomes free (see illustrations). 19 Remove the polished glaze from the surface of the disc with sand/emery paper. Use small, circular motions to avoid producing a directional finish on the surface.
Refitting 20 If a new disc Is being fitted, remove the protective coating from the surface U9ing an appropriate solvent. 21 Locate Ihe disc on ihe hub so that the roadwheel bolt and locating stud holes are all correctly lined up; use the alignment marks made during removal. If the disc is being removed in an attempt to improve seating and hence runout, turn the disc through 180° and then refit it. 22 Refit the locating stud and retaining screw, tightening them securely. 23 Re-check the disc runout, using one of the methods described earlier in this Section. 24 Refil the brake caliper and mounting bracket assembly to the hub carrier. Coat the threads of the mounting bolts with locking compound, then tighten them to the specified torque. 25 Depress the brake pedal several times to bnng the brake pads into contact with the disc. 26 Refit the roadwheel and lower the vehicle to the ground. Tighten the roadwheel bolts to the specified torque. 27 Check the hydraulic fluid level as described in Weekly checks.
4,18b ... and lift off the disc as It becomes free