GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

2 and 4-Wheel Drive



See Figures 1 and 2

The vehicles covered by this manual use a variety of wheel styles, but from the factory they are all one piece rims with 5 bolt holes in a bolt circle of 4.75 in. (120.6mm) for vehicles through 1991 or 5 in. (127mm) for 1992-93 vehicles. Wheels are also available in a variety of standard sizes from 14 x 6 in. (355.6 x 152.4mm) to 15 x 7 in. (381 x 177.8mm). The MFI-Turbo was equipped with 16 x 8 in. (406.4 x 203.2mm). Most vehicles are equipped with a space saver spare, for EMERGENCY USE ONLY, which comes in a 16 x 4 in. (406.4mm x 101.6mm) and 15 x 4 in. (381 x 101.6mm) sizes.

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Fig. Fig. 1: Most trucks are equipped with a spare tire mounted to a hanger bracket under the bed

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Fig. Fig. 2: Wheel lug tightening sequence for a 5-lug wheel

  1. When removing a wheel, loosen all the lug nuts with the wheel on the ground, then raise and safely support the vehicle. If you are working at home (not on a roadside emergency) support the truck safely using jackstand(s).
  3. If the wheel is stuck or rusted on the hub, make all the lug nuts finger tight, then back each one off 2 turns. Put the truck back on the ground and rock it side to side. Get another person to help if necessary. This is far safer than hitting a stuck wheel with the vehicle on a jack or jackstands.
  5. When installing a wheel, tighten the lug nuts in a rotation, skipping every other one.
  7. Always use a torque wrench to avoid uneven tightening, which will distort the brake drum or disc. For vehicles through 1991 (except MFI-Turbo) tighten the lug nuts on steel wheels to 73 ft. lbs. (100 Nm) and the nuts on aluminum alloy wheels to 90 ft. lbs. (120 Nm). For 1992 stock wheels, tighten the nuts to 90 ft. lbs. (120 Nm). For 1991-92 MFI-Turbo wheels, tighten the lug nuts to 100 ft. lbs. (140 Nm). On 1993 vehicles equipped with the stock wheels, tighten the lug nuts to 95 ft. lbs. (130 Nm).


See Figures 3 and 4

Wheels can be distorted or bent and not effect dry road handling to a noticeable degree. Out of round wheels will show up as uneven tire wear, or will make it difficult to balance the tire. Wheel runout can be checked with the wheel on or off the truck and with the tire on or off the rim. If measurement is to be made with the wheel off the truck, you will need an accurate mounting surface such as a wheel balancer.

Both lateral and radial runout should be measured using a dial gauge. Lateral runout is a sideways vibration causing a twist or wobble and is measured on a side surface. On a tire and wheel assembly, measure the sidewall of the tire, as close as possible to the tread shoulder design edge. On a rim, measure the runout on the flange.

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Fig. Fig. 3: Measuring lateral runout

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Fig. Fig. 4: Measuring radial runout

Radial runout is the egg-shaped difference from a perfect circle. On a tire and wheel assembly, measure radial runout from the center of the tire tread rib, although other tread ribs can be measured, if necessary. The rim may be measured on either flange if the tire is removed.

  1. Use a dial gauge to measure the runout of the wheel or tire and wheel assembly, as applicable.
  3. For steel wheels, the lateral runout limit is 0.045 in. (1.143mm), the radial runout limit is 0.040 in. (1.015mm).
  5. For aluminum alloy wheels, the limit for both runout directions is 0.030 in. (0.762mm).