tire size FIAT PUNTO 1996 176 / 1.G Workshop Manual

2D*10 Engine removal and overhaul procedures
failure, (he cause must be corrected (where applicable) before the engine is reassembled, to prevent it from happening again. 3 When examining the bearing shells, remove them from the cylinder block/crankcase, Ihe main bearing caps, the connecting rods and the connecting rod big-end bearing caps. Lay them out on a clean surface in the same general position as their location in the engine. This will enable you to match any bearing problems with the corresponding crankshaft journal. Do not touch any shell's bearing surface with your fingers while checking it. 4 Din and other foreign matter gets into the engine in a variety of ways. It may be left in the engine during assembly, or It may pass through fillers or the crankcase ventilation system. It may get into the oil, and from there into the bearings. Metal chips from machining operations and normal engine wear are often present. Abrasives are sometimes left In engine components after reconditioning, especially when parts are not thoroughly cleaned using the proper cleaning methods. Whatever the source, these foreign objects often end up embedded In the soft bearing material, and are easily recognised. Large particles will not embed in the bearing, and will score or gouge the bearing and journal. The best prevention for this cause of bearing failure Is to clean all parts thoroughly, and keep everything spotlessly-clean during engine assembly. Frequent and regular engine oil and filter changes are also recommended. 5 Lack of lubrication (or lubrication breakdown) has a number of interrelated causes. Excessive heat (which thins the oil), overloading (which squeezes the oil from the bearing face) and oil leakage (from excessive bearing clearances, worn oil pump or high engine speeds) all contribute to lubrication
breakdown. Blocked oil passages, which can be the result of misaligned oil holes in a bearing shell, will also oil-starve a bearing, and destroy it. When lack of lubrication is the cause of bearing failure, the bearing materiel is wiped or extruded from the steel backing of Ihe bearing. Temperatures may increase to the point where the steel backing turns blue from overheating. 6 Driving habits can have a definite effect on bearing life. Full-throttle, low-speed operation (labouring ihe engine) puts very high loads on bearings, tending to squeeze out the oil film. These loads cause the beanngs to flex, which produces fine cracks in the bearing face (fatigue failure). Eventually, the bearing material will loosen in pieces, and tear away from Ihe steel backing. 7 Short-distance driving leads to corrosion of bearings, because insufficient engine heat is produced to drive off the condensed water and corrosive gases. These products collect in the engine oil, forming acid and sludge. As the oil Is carried to the engine bearings, the acid attacks and corrodes the bearing material. 8 Incorrect bearing installation during engine assembly will lead to bearing failure as well. Tight-fitting bearings leave insufficient bearing running clearance, and will result in oil starvation. Dirt or foreign particles trapped behind a bearing shell result in high spots on the bearing, which lead to failure. 9 Do not touch any shell's bearing surface with your fingers during reassembly: there is a risk of scratching the delicate surface, or of depositing particles of dirt on ft. 10 As mentioned at the beginning of this Section, the bearing shells should be renewed as a matter of course during engine overhaul; to do otherwise is false economy.
Selection 11 Main and big-end bearings are available in standard sizes and a range of undersizes to suit reground crankshafts • refer to the Specifications for details. The engine reconditioner will select the correct bearing shells for a machined crankshaft. 12 The running clearances can be checked when the crankshaft is refitted with its new bearings.
11 Engine overhaul -reassembly sequence
1 Before reassembly begins, ensure that all new parts have been obtained, and that all necessary tools are available. Read through the entire procedure to familiariss yourself with the work Involved, and to ensure that ail items necessary for reassembly of the engine are at hand. In addition to all normal tools and materials, thread-locking compound will be needed. A tube of sealant will also be required for the joint faces that are fitted without gaskets.
2 In order to save time and avoid problems, engine reassembly can be carried out in the following order: a) Crankshaft (Section 12). b) Piston/connecting rod assemblies (Section 7). c) Oil pump (see Part A, B or C - as applicable). d) Sump (see Pan A, BorC-as applicable). e) Flywheel/driveplate (see Part A, B or C • as applicable). 1) Cylinder head (see Part A B or C - as applicable). g) Coolant pump (see Chapter
3)
h) Timing belt tensioner and sprockets, and timing belt (See Part A, B or C- as applicable). I) Engine external components, 3 At this stage, ail engine components should be absolutely clean and dry, with all faults repaired. The components should be laid out on a completely clean work surface.
12 Crankshaft- % refitting and main bearing S running clearance check ^
Crankshaft - initial refitting 1 Crankshaft refitting Is the first stage ol engine reassembly following overhaul. At this point, it is assumed that the crankshaft, cylinder block/crankcase and beanngs have been cleaned, inspected and reconditioned or renewed. 2 Place the cylinder block on a clean, level work surface, with the crankcase facing upwards. Where necessary, unbolt the bearing caps and lay them out in order to ensure correct reassembly. If they are still in place, remove the bearing shells from the caps and the crankcase and wipe out the inner surfaces wilh a clean rag - they musl be kept spotlessly clean. 3 Clean the rear surface of the new bearing shells with a rag and fit ihem on Ihe bearing saddles. Ensure that the orientation lugs on the shells engage with the recesses in the saddles and lhat the oil holes are correctly aligned. Do not hammer or otherwise force the bearing shells into place. It Is critically important that the surfaces of the bearings ore kept free from damage and contamination. 4 Give the newly fitted bearing shells and the crankshaft journals a final clean with a rag. Check that the oil holes In the crankshaft are free from dirt, as any left here will become embedded In the new bearings when Ihe engine is first started. 5 Carefully lay the crankshaft In the crankcase, taking care not to dislodge the bearing shells (see illustration}.
Main bearing running clearance check 8 When Ihe crankshaft and bearings are refitted, a clearance must exist between them

Suspension and steering 10*11
13.11b ... and left-hand steering gear-to-subframe bolts
hooked onto the engine lifting eyelet on the cylinder head. Working underneath the vehicle, unbolt and remove the transmission-lo-subframe rear mounting bracket. 13 Position a trolley jack under the right hand skle of the subframe crossmember. Raise the jack to take the weight of the crossmember
and
the attached components. 14 With reference to Section 4, slacken and remove the two bolts that secure the suspension lower arm rear bush to the subframe. Slacken and withdraw the subframe-to-bodywork bolt, located adjacent to the rear of the suspension lower arm. Throad two flange head bolts of the same thread size, but approximately 25 mm longer into the vacated holes, then carefully lower
the
trolley jack and allow ihe subframe to rest on the heads of the temporary bolts (see (lustration), 15 Repeat the operations in paragraphs 13 end 14 at the left-hand side of the vehicle. On completion, the subframe should be resting at
&
height approximately 25 mm lower than normal. 16 The additional clearance will now permit the steering gear pinion to be lowered away from the bulkhead. When the end of the pinion has cleared Ihe aperture, manoeuvre the entire steering gear assembly through the *tiae?arch.
Refitting 17 Refitting is a reversal of removal, noting
the
following points: s) Remote the temporary bolts and refit the original length fixings.
13.14 Slacken and remove the subframe-to-bodywork bolts (arrowed)
b) Tighten all fixings to the specified torque settings. c) Refill the hydraulic system with the specified grade and quantity of power steering fluid (see Lubricants and fluids In Weekly checks), then thoroughly bleed the system as described in Section 15. d) On completion, have the front wheel alignment checked at the earliest oppor-tunity by a Flat dealer or a tyre specialist.
14 Steering gear rubber gaiters - renewal <
Note: New gaiter retaining clips should be used on refitting. 1 Remove the relevant track-rod end as described in Section 17. 2 If not already done, unscresv the track-rod end locknut from Ihe end of the track-rod. 3 Mark the correct fitted position of the gaiter on the track-rod, then release the gaiter securing clips. Slide the gailer from the steering gear, and off the end of the track-rod. 4 Thoroughly clean tho track-rod and the steering gear housing, usrng fine abrasive paper to polish off any corrosion, burrs or sharp edges, which might damage the new gaiter sealing lips on installation. Scrape off all the grease from the old gaiter, and apply it to the track-rod inner balljoint. (This assumes that grease has not been lost or contaminated as a result of damage to the old gaiter. Use fresh crease if In doubt.) 5 Carefully slide the new gaiter onto the track-rod. and locate it on the steering gear housing. Align the outer edge of the gaiter with the mark made on the track-rod prior to removal, then secure it in position with new retaining clips. 6 Screw the track-rod end locknut onto the end of the track-rod. 7 Refit the track-rod end as described in Section 17.
15 Power steering hydraulic system • bleeding ^
General 1 The following symptoms indicate that there is air present In the power steering hydraulic system: a) Generation of air bubbles in fluid reservoir. b) Clicking noises from power steering pump. c) Excessive buzzing or groaning from power steering pump. 2 Note that when the vehicle Is stationary, or while moving the steering wheel slowly, a hissing noise may be produced In the steering gear or the fluid pump. This noise is inherent in the system, and does not indicate any cause for concern.
Bleeding 3 Chock the rear wheels, apply the handbrake, then jack up the front of the vehicle and support securely on axle stands (see Jacking and vehicle support). 4 Check the fluid level in the power steering fluid reservoir (bear in mind that the vehicle will be tilted, so the level cannot be read accurately), and if necessary top-up to just above the relevant level mark. 5 Have an assistant tum the steering quickly from lock to lock, and observe tho fluid level, if the fluid level drops, add more fluid, and repeat the operation until the fluid level no longer drops. Failure to achieve this within a reasonable period may indicate a leak in the system. 6 Stan the engine and repeat the procedure described In the previous paragraph. 7 Once the fluid level has stabilised, and all air has been bled from the system, lower the vehicle to the ground.
16 Power steering pump - Sk removal and refitting ^
Removal 1 Drain as much fluid as possible from the power steering reservoir, using a pipette or an old poultry baster. 2 Remove the clip and disconnect the rubber fluid supply hose from the port on the top of the power steering pump. Be prepared for an amount of fluid loss • position a container underneath the port and pad the surrounding area with absorbent rags. 3 Slacken the union and disconnect the fluid delivery hose from the side of the power steering pump. Again, be prepared for an amount of fluid loss. 4 Unscrew tho clamp bolt and through-bolt at either end of the drivebelt guard, then detach Ihe guard from the power steering pump (see illustrations). 5 Partially unscresv the two power steering pump mounting bolts then rotate the pump towards the engine slightly, to release the tension from the belt. Carefully ease the drivebelt from the pump pulley.
16.4a Unscrew the clamp bolt...