IRREGULAR TIRE WEAR WITH ALL SEASON TIRES

MODELS AFFECTED: 1985-1986 FLEETWOOD BROUGHAM AND 1985 ELDORADO AND SEVILLE WITH ALL SEASON TIRES

This bulletin supersedes Serviceman Bulletin T-86-49, Group 3E, which should be destroyed. The labor operation originally listed as T6149 has been changed to T6151.

Condition

Some 1985-1986 Fleetwood Broughams and 1985 Eldorados and Sevilles may experience irregular tire wear on non-drive axles with original equipment all season tires (with "M & S" rating on sidewall). The wear may be identified as a cupping or heel and toe condition, usually on the outer shoulder of the tire. If allowed to continue, premature wear 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.

Service Procedure

Tire wear should be inspected:

1. If only slight cupping is noticed, and the cross grooves in the tire outside shoulder are still visible (see Figure 1), tires should be rotated using the modified "X" rotation pattern (see Figure 2). The vehicle alignment should then be checked and reset if necessary to the new alignment specifications in this bulletin. Both before and after alignment measurements must be recorded on the Repair Order. The importance of regular tire rotation and proper inflation pressures must be stressed to the customer.

2. If the cupping is severe and/or the cross grooves in the outside shoulder are not visible (see Figure 1), tire replacement will be necessary. A maximum of two replacement tires will be available for vehicles under 12 months and 12,000 miles. Replacement tires must be obtained directly from Uniroyal tire company by calling the following toll-free number:

1-800-231-5893 (outside Texas) 1-800-833-5906 (in Texas)

Dealers must supply owner's name, VIN, mileage, dealer code and tire size and model (e.g., Royal Seal). Tires will be furnished on a direct bill basis to dealers. The bill from Uniroyal will contain the vehicle VIN; dealers should retain a copy of this bill for their records. Any claims submitted which are not substantiated by Uniroyal will be debited for the entire amount of the claim.

Old tires must be held for scrapping by a Cadillac representative. They must be rendered unusable by drilling four holes through the tire serial number, located on the back sidewall.

Mount new tires aligning the yellow mark on the tire with the valve stem on the wheel (see Figure 3). Balance and install on non-drive axle positions. Check alignment of non-drive axle and reset as necessary; see new alignment specifications in this bulletin. Both before and after alignment measurements must be recorded on the R.O. Stress the importance of regular tire rotation and proper inflation pressures to the customer.

Revised Fleetwood Brougham Front Alignment Specifications

Toe: Per Wheel .06 deg. +/- .05 deg. Sum .12 deg. +/- .10 deg. Camber: .25 deg. +/- .25 deg. Caster: 3.00 deg. +/- .50 deg.

Revised Eldorado and Seville Rear Alignment Specifications

Toe: Sum .10 deg. +/- .10 deg.

For warranty purposes, use one of the following labor Operations:

FAILURE LABOR LABOR NET DESCRIPTION CODE OPERATION HOURS ITEM ----------- ------- --------- ----- ---- - Rotate tires using modified 06 T - 6151 * -- X rotation (includes lock nuts) and align front or rear suspension

* Fleetwood Brougham (front suspension) 1.4 Hrs. Eldorado and Seville (rear suspension) 1.2 Hrs.

- Mount and batance two tires 06 T - 6150 ** *** (includes lock nuts) and align front or rear suspension

** Fleetwood Brougham (front suspension) 1.7 Hrs. Eldorado and Seville (rear suspension) 1.5 Hrs.

Dealers are eligible for .2 administrative allowance as "other labor hours" if tires are replaced.

*** The Uniroyal tire invoice amount should be entered as a net item on the 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.