1999 FIAT PUNTO run flat

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,

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...

Suspension and steering 10*13
the skill required to use It properly, the checking and adjustment of these settings Is best left to a Fiat dealer or similar expert. Most tyre-fitting shops now possess sophisticated checking equipment. 3 For accurate checking, the vehicle must be at the kerb weight specified in Dimensions and weights. 4 Before starting work, check first that the tyre sizes and types are as specified (see Tyre pressures in Weekly checks), then check tyre pressures and tread wear. Also check roadwheel run-out, the condition of the hub bearings, the steering wheel free play and the condition of the front suspension components (Steering and suspension check in Chapter 1A or
1B).
Correct any faults found. 6 Park the vehicle on level ground, with the front roadwheeis in the straight-ahead position. Rock the rear and front ends to settle the suspension. Release the handbrake and roll the vehicle backwards approximately 1 metre, then forwards again, to relieve any stresses in the steering and suspension components. 6 Two methods are available to the home mechanic for checking the front wheel toe setting. One method is to use a gauge to measure the distance between the front and rear inside edges of the roadwheeis. The other method is to use a scuff plate, in which each front wheel is rolled across a movable plate which records any deviation, or scuff, of the tyre from the straight-ahead position as It moves across the plate. Such gauges are available in relatively-inexpensive form from accessory outlets. It Is up to the owner to decide whether the expense is justified, In view of the small amount of use such equipment would normally receive. 7 Prepare the vehicle 8S described in paragraphs 3 to 5 above.
8 If the measurement procedure is being used, carefully measure the distance between the front edges of the roadwheel rims and the rear edges of the rims. Subtract the front measurement from the rear measurement, and check that the result is within the specified range. If not, adjust the toe setting as described in paragraph 10. 9 If scuff plates are to be used, roll the vehicle backwards, check that the roadwheeis are in the straight-ahead position, then roll it across the scuff plates so that each front roadwheel passes squarely over the centre of its respective plate. Note the angle recorded by the scuff plates. To ensure accuracy, repeat the check three times, and take the average of the three readings, if the roadwheeis are running parallel, there will of course be no angle recorded; If a deviation value Is shown on the scuff plates, compare the reading obtained for each wheel with that supplied by the scuff plate manufacturers. If the value recorded is outside Ihe specified tolerance, the toe setting is incorrect, and must be adjusted as follows. Adjustment 10 Apply the handbrake, then jack up the front of the vehicle and support it securely on axle stands (see Jacking and vehicle support). Turn the steering wheel onto full-left lock, and record the number of exposed threads on the right-hand track-rod. Now turn the steering onto full-right lock, and record the number of threads on the left-hand side. If there are the same number of threads visible on both sides, then subsequent adjustment should be made equally on both sides. If there are more threads visible on one side than the other, it will be necessary to compensate for this during adjustment Note: It is important to ensure that, after adjustment, the same number of threads are visible on the end of each track-rod.
11 First clean the track-rod threads; If they are corroded, apply penetrating fluid before starting adjustment. Release the steering gear rubber gaiter outboard clips, then peel back the gaiters and apply a smear of grease, so that both gaiters are free and will not be twisted or strained as their respective track-rods are rotated. 12 Use a straight-edge and a scriber or similar to mark the relationship of each track-rod to the track-rod end. Working on each track-rod end in tum, unscrew its locking nut. 13 Alter the length of the track-rods, bearing In mind the note in paragraph 10, by screwing them into or out of the track-rod ends. Rotate the track-rod using an open-ended spanner fitted to the flats provided. If necessary, counterhold the track-rod end using a second spanner. Shortening the track-rods (screwing them Into their track-rod ends) will reduce toe-in and increase toe-out. 14 When the setting Is correct, hold the track-rods and securely tighten the locking nuts. Check that the balljoints are seated correctly In their sockets, and count the exposed threads on the ends of the track-rods. If the number of threads exposed is not the same on both sides, then the adjustment has not been made equally, and problems will be encountered with tyre scrubbing in turns; also, the steering wheel spokes will no longer be horizontal when the wheels are in the straight-ahead position. 15 When the track-rod lengths are the same, lower the vehicle to the ground and re-check the toe setting; readjust if necessary. When the setting is correct, tighten the locking nuts. Ensure that the steering gear rubber gaiters are seated correctly and are not twisted or strained, then secure them In position with new retaining clips.
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