REVISED:PREMATURE TIRE WEAR REPAIR/ROTATION PROCEDURE

MODELS AFFECTED: 1985-86 CENTURYS 1985 LESABRES 1985-86 LESABRE AND ELECTRA ESTATE WAGONS 1985-86 REGALS 1985 RIVIERAS

Condition

Some subject models with original equipment all season tires 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 wearout 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

The following models that are equipped with All Season Firestone "Supreme", General "Ameriway XT", Goodyear "Vector", or Uniroyal "Tiger Paw Plus" tires may experience this wear condition:

Model Tire Location ----- ------------- 1985-86 Centurys Rear Position Only 1985 LeSabres Front Position Only 1985-86 LeSabre & Electra Estate Wagons Front Position Only 1985-86 Regals Front Position Only 1985 Riviera Rear Position Only

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 Bill" basis to the dealer. Replacement tires must be obtained directly from the tire company by calling the following toll-free number:

Firestone - (216) 379-7096 (Collect) General - 1-800-TIRE-FIX Goodyear - 1-800-TIRE-TEC Uniroyal - 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 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. Whenever tires are replaced or rotated, perform the following:

A. On LeSabre, LeSabre and Electra Wagons, and Regals, front alignment must be measured. For best tire wear, reset toe to zero. Camber and caster should be set to specification.

B. On Rivieras, reset rear toe to Zero.

C. On Centurys, install rear axle shim kit, Part No. 14094481, as explained in Service Bulletin 86-3-3, dated January, 1986. This will reduce rear toe.

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 Buick Zone Office. Vehicle mileage must be within the specified parameters to be eligible. Attach originals of customer receipts to repair order.

Disposition of Replaced Tires

All replaced tires must be properly tagged and available for scrapping by Buick Zone personnel.

Warranty Information

For Warranty purposes, use the following one applicable labor operation.

Operation* Operation Number --------- ---------------- - Rotate 4 tires and align suspension T5108 or install Shim Kit

Model Labor Description Labor Hours ----- ----------------- ----------- Century Rotate Tires & Install 1.4 Shim Kit

LeSabre, LeSabre & Electra Wagons & Regals Rotate Tires & Align 1.4 Front Suspension

Rivieras Rotate Tires & Align 1.2 Rear Suspension

Operation* Operation Number ---------- ---------------- - Mount and balance 2 tires & Firestone Tires T5109 align suspension or install General Tires T5110 Shim Kit. Goodyear Tires T5111 Uniroyal Tires T5112

Model Labor Description Labor Hours ----- ----------------- ----------- Century Replace Rear Tires & 2.0 Install Shim Kit

LeSabre, LeSabre & Replace Front Tires & 2.0 Electra Wagons & Regals Align Front Suspension

Rivieras Replace Rear Tires & 1.7 Align Rear Suspension

List .2 hr. for Administration in "Other Hours" column of Warranty Claim.

List Net Cost of tires in "Sublet" Column of warranty claim.

*NOTE: 1. USE FAILURE CODE 06 (WORN) FOR ALL ABOVE LABOR OPERATIONS.

2. ALL OF THE ABOVE LABOR OPERATIONS INCLUDE AN ALLOWANCE FOR 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.