On some 1984 'A' and 'X' series vehicles, there may be an audible repeated 'clunk' in the rear brakes during light brake pedal pressure. The possible cause for this 'clunk' may be the slight in and out movement of the rear brake shoes. This movement may be caused by an 'screw' type machined inner brake drum surface. Technicians should check for this condition during the new vehicle inspection road test. Both rear drums should be turned approximately .127 mm. (.005 inch) on a brake lathe to correct this condition prior to delivery of the vehicle.
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.