rims FIAT PUNTO 1999 176 / 1.G Workshop Manual

o»i4 Weekly checks
Tyre condition and pressure
l( is very important that tyres are In good condition, and at the correct pressure - having a tyre (allure at any speed is highly dangerous. Tyre wear is influenced by driving style • harsh braking and acceleration, or fast cornering, will ail produce more rapid tyre wear. As a general rule, the front tyres wear out faster than the rears. Interchanging the tyres from front to rear ("rotating' the tyres) may result in more even wear. However, if this is completely effective, you may have the expense of replacing ail four tyres at once! Remove any nails or stones embedded In the tread before they penetrate the tyro to cause deflation. If removal of a nail does reveal that
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the tyre has been punctured, refit the nail so (hat its point of penetration is marked. Then Immediately change the wheel, and have the tyre repaired by a tyre dealer. Regularly check the tyres for damage (n the form of cuts or bulges, especially in the sidewails. Periodically remove the wheels, and clean any dirt or mud from the Inside and outside surfaces. Examine the wheel rims for signs of rusting, corrosion or other damage, Light alloy wheels are easily damaged by •kerbing"1 whilst parking; steel wheels may also become dented or buckled. A new wheel Is very often the only way to overcome severe damage.
New tyres should be balanced when they are fitted, but it may become necessary to re-balance them as they wear, or if the balance weights fitted to the wheel rim should fall off. Unbalanced tyres will v/ear more quickly, as will the steering and suspension components. Wheel imbalance is normally signified by vibration, particularly at a certain speed (typically around 50 mph). If this vibration is fett only through the steering, then II Is likely that |ust the front wheels need balancing. H, however, the vibration is felt through the whole car. the rear wheels could be out of balance. Whoel balancing should be carried out by a tyre dealer or garage.
-j Tread Depth • visual check The original tyres have tread wear safety bands {8}, which wiU appear when the tread depth reaches approximately 1.6 mm. The band positions are indicated by a triangular mark on the tyre sidewail (A).
Tyre tread wear patterns
2 Tread Depth * manual check Alternatively, tread wear can be monitored with a simple, inexpensive device known as a tread depth indicator gauge.
2 Tyre Pressure Check Check the tyre pressures regularly with the tyres cold. Do not adjust the tyre pressures immediately alter the vehicle has been used, or an inaccurate setting will result Tyre pressures are shown on page 0*18.
Shoulder Wear Centre Wear Uneven Wear
Underinflatlon {wear an both sides) Under-lnflatton will cause overheating of the tyre, because the tyre will flex too much, and the tread will not sit correctly on the road surface. This will cause a loss of grip and excessive wear, not to mention the danger of sudden tyre failure due to heat build-up. Check and adjust pressures Incorrect wheel camber (wear on one side] Repair or renew suspension parts Hard cornering Reduce speed!
Overinflation Over-inflation will cause rapid wear of the centre part of the tyro tread, coupled with reduced grip, harsher ride, and the danger of shock damage occurring in the tyre casing. Check and adjust pressures
It you sometimes have (o inflate your car's tyres to the higher pressures specified tor maximum load or sustained high speed, don't forget to reduce the pressures to normal afterwards.
Front tyres may wear unevenly as a result of wheel misalignment. Most lyre dealers and garages can check and adjust the wheel alignment (or 'tracking") for a modest charge. Incorrect camber or castor Repair or renew suspension parts Malfunctioning suspension Repair or renew suspension parts Unbalanced wheel Balance tyres Incorrect toe setting Adjust front wheel alignment Note: The feathered edge of I he treed which typifies toe wear is best checked by feel.

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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