IRREGULAR/PREMATURE TIRE WEAR REPAIR/ROTATION PROCEDURE

1985-86 CELEBRITY MODELS WITH 'ALL SEASON Model and Year: TIRES' REAR POSITION ONLY -1985-86 CAPRICE & MONTE CARLO MODELS WITH 'ALL SEASON TIRES' FRONT POSITION ONLY -1985-86 ASTRO VAN, "G" VAN, "C/K TRUCKS, AN "S/T" TRUCKS EQUIPPED WITH 'ALL SEASON TIRES' FRONT POSITION ONLY

TO: ALL CHEVROLET DEALERS

CONDITION

Some 1985-1986 Celebrity models, 1985-1986 Caprice and Monte Carlo models, and some 1985-86 light duty trucks with original equipment all season tires ("M & S" rating on sidewall) may experience premature/irregular tire wear on non-drive axles. The wear may be identified as a cupping condition, usually on the outer shoulder of the tire. If allowed to continue, premature wear out of tread may occur.

CAUSE

The single, most contributing cause of this type of wear, except for abusive driving, is excessive toe-in. Lack of tire rotation and low inflation pressures will also exaggerate this condition.

VEHICLES INVOLVED

1985-1986 Celebrity models with 'all season tires'. REAR POSITION ONLY.

1985-1986 Caprice and Monte Carlo models with 'all season tires'. FRONT POSITION ONLY.

1985-1986 "M" van, "G" van, "C/K" trucks, and "S/T" trucks equipped with all season tires as follows: FRONT POSITION ONLY.

Firestone "Supreme" Goodyear "Vector" General "Ameriway XJ" Uniroyal "Tiger Paw Plus"

SERVICE PROCEDURE

1. Tire wear should be inspected:

A. If only slight cupping is noticed, and the cross grooves in the tire's outside shoulder are still visible'(see Figure 1), the tires should be rotated. The modified "X" pattern should be used (See Figure 2). This method will best equalize wear after a few thousand miles.

B. If the cupping or wear is severe, and/or the cross grooves in the outside shoulder are not visible, tire replacement may be necessary. Tire replacement, if required, will be made with the same brand and type tire as original equipment. These tires will be furnished on a "direct billed" basis to the dealer. Replacement tires must be obtained direct from the tire company by calling one of the following toll-free numbers:

Firestone - (216) 379-7096 (collect) General - 1-800-TIRE-FIX Goodyear - 1-800-TIRE-TEC Uniroyal - 1-800-231-5893 (EXCEPT TEXAS) 1-800-833-5906 (TEXAS)

Dealers must supply owner's name, VIN, mileage, dealer code, tire make, size and description (i.e., Whitewall, Brand Name, etc.) A maximum of two (2) tires per vehicle will be provided on a "one time only" basis at no charge to the customer for the first 12,000 miles or 12 months.

2. A. On Caprice and Monte Carlo models, whether tires are replaced or rotated, front alignment must be measured. For the best tire wear, reset toe to zero. Camber and caster should be set to specification.

B. On Celebrity models, install rear axle shim kit, P/N 14094481, as explained in Chevrolet Dealer Service Bulletin 86-23. This will reduce rear toe.

C. On "M" van, "G" van, "C/K" trucks, and S/T trucks, whether tires are replaced or rotated, front alignment must be measured. For best tire wear, reset toe to zero. Camber and caster should be set to specification.

D. IMPORTANT ON ALL VEHICLES To further help minimize tire wear, stress the importance of regular tire rotation to the owner. The modified "X" pattern at 7,500 miles is recommended. Also, point out the importance of proper inflation pressure, as listed on the tire placard on the driver's door edge.

3. Old tires must be scrapped by drilling four (4) holes through the tire's serial number, located on the back sidewall.

Mount new tires with the yellow mark or orange label on the tire at the valve stem on the wheel. Balance and install on non-drive axle positions.

CUSTOMER REIMBURSEMENT

Claims for customer reimbursement of previously paid repairs due to the described tire wear condition, accompanied by originals of paid receipts verifying vehicle mileage, should be submitted to the Zone Consumer Relations Office. Vehicle mileage must be within the specified parameters to be eligible. Reimbursement amount requested should be shown as a sublet repair. Do not list parts and labor. Attach originals of customer receipts to repair order.

WARRANTY CLAIM INFORMATION

The above services are consistent with new vehicle warranty and are to be performed at no charge to the owner for the first 12,000 miles or 12 months.

For warranty purposes, use the following applicable labor operations and submit tires at net cost:

Tire Labor Labor Description* Model Manuf. Operations Hours ------------- ----- ------- ---------- ----- 1. Rotate 4 tires Light (Modified "X" Pattern) Trucks and align front suspension B&G N/A T-1159 1.4

2. Mount and balance - 2 tires B&G Firestone T-1160 2.0 and align front suspension Light General T-1161 2.0 Trucks Goodyear T-1162 2.0 Uniroyal T-1163 2.0

3. Rotate 4 Tires (Modified "X" Pattern) and install shim kit A N/A T-1164 1.4

4. Mount and balance - 2 tires A Firestone T-1165 2.0 and install shim kit General T-1166 2.0 Goodyear T-1167 2.0 Uniroyal T-1168 2.0

5. Administration Time N/A N/A N/A .2 hrs

*NOTE: 1. Use failure Code 06 (Worn) for all above labor operations.

2. All of the above Labor Operations include an allowance for wheel locks or locking wheel covers.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.