GM 96062139
Brake Drum

Replace a damaged brake drum since it creates safety issues but fix a slight brake drum scuff mark with metal smoothing. Severe score marks require total brake drum surface restoration. A brake drum can undergo refinishing when its out-of-round or tapered shape does not reach critical levels. Drums need refinishing until their braking surface reaches maximum sizes of 7.16 inches for 2-Door and 7.95 inches for 4-Door models but must be replaced if metal cannot be removed to these standards due to altered heat dissipation and part distortion effects. Using sharp cutting tools works better than dull tools since poor surface quality through poor tools weakens brake performance. The use of vibration control tools will improve surface smoothness at 200 rpm spindle speed. Any rough cut needs a crossfeed setting between 0.25 mm and 0.15 mm per rotation yet finishes cuts require not more than 0.05 mm crossfeed per rotation. If drums meet their original diameter requirements after polishing they must be substituted for new ones. The installer must keep manufacturing balance weights in place during brake drum installation. After refinishing the drums must undergo balance checks on an off-vehicle tool and need replacement when imbalance occurs.

Insert a screwdriver into the backing plate plug until it contacts the shoe lever stopper, then push the screwdriver in the direction of the arrow.