PREMATURE BREAK WEAR (LUBRICANT DEPLETION)

SUBJECT: PREMATURE BRAKE WEAR (AEROSHELL #5 LUBRICANT ON CALIPER FRICTION SURFACES)

MODELS: 1990-92 TOPKICK/KODIAK W/JE3 HYDRAULIC BRAKES

Owners of some 1990-92 5H, 6H, and 7H Topkick/Kodiak trucks with hydraulic brakes may comment on premature brake wear. The premature brake wear condition may be caused by an early depletion of caliper rail slide lubricant. This could result in premature brake wear by preventing proper caliper slide orientation.

It is recommended that an ample coating of Aeroshell #5 grease be applied to the V-way surfaces of the caliper housing (See Figure 1), the anchor plate rail surfaces, the caliper support spring, and the caliper support key after thoroughly cleaning these areas. Currently this lubricant can be procured from local Shell distributors or their retail stores in various size containers including 1 lb. cans and 14 oz. cartridges, in case lots.

The recommended maintenance interval for lubrication is 6 months or 18 thousand miles. This interval should be appropriately reduced for vehicles operating under severe or abrasive conditions.

Refer to section 5 of the appropriate service manual for caliper service procedures.

This recommendation will be included in future issues of the Service Manual, the Maintenance Schedule and the Owner's Manual for models applicable.

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.