IRREGULAR/PREMATURE TIRE WEAR REPAIR/ROTATION PROCEDURE

MODELS: 1985-86 LIGHT DUTY MODELS EQUIPPED WITH ALL SEASON TIRES

CONDITION

Some 1985-1986 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, pre-mature 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 M Van, G Van, C/K Trucks, and S/T Trucks equipped with all season tires as follows:

Front Position Only

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

SERVICE PROCEDURE

1. Front tire wear should be inspected. Use one of the following procedures to determine if tire replacement is necessary.

Firestone and Goodyear

A. If outer shoulder wear has progressed to the point that the outer shoulder is smooth (no tread visible), replace both front tires.

B. If the outer shoulder tread is visible, use a tread depth gage to determine extent of wear. Measure tread depth at location shown in Figure No. 2. If tread depth is 5/32" or less, tire replacement will be necessary. If greater than 5/32", the tires should be rotated using the modified "X" pattern (See Figure No. 1). This method will best equalize wear after a few thousand miles.

General and Uniroyal

A. If only slight cupping is noticed, and the cross grooves in the tire's outside shoulder are still visible (See Figure No. 3), the tires should be rotated. The modified "X" pattern should be used (See Figure No. 1). This method will best equalize wear after a few thousand miles.

B. If the cupping or wear is severe, and the cross grooves in the outside shoulder are not visible, tire replacement will be necessary (See Figure No. 4).

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 1-800-426-4889 (Ohio) 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.)

NOTE: A MAXIMUM OF TWO 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, WHICHEVER OCCURS FIRST.

2. A. 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.

B. 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 considered part of warranty claim material and be held for scrapping by a GMC representative. They must be rendered unusable by drilling four holes through the tire serial number, located on 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, time and service 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 Manu- Labor Labor Description* Model facturer Operations Time ------------ ----- -------- ---------- ---- 1. Rotate 4 Light N/A T7240 1.4 Hrs. tires Duty (Modified Trucks "X" Pattern) and Align Front Suspension

2. Mount and Light Firestone T7245 2.0 Hrs. balance-2 Duty General T7250 2.0 Hrs. Tires and Trucks Goodyear T7255 2.0 Hrs. Align Front Uniroyal T7260 2.0 Hrs. Suspension

3. Adminis- N/A N/A N/A .2 Hrs. tration Time

*NOTE: 1. Use Failure Code 06 (wom) for all above labor operations.

2. All of the above labor operations include an allowance for wheel locks or locking wheel covers.

List net cost of tires in "Sublet" column of warranty claim.

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.