The following procedure requires the use of GM brake adjustment tool J-4735 or its equivalent.
Raise and support the rear of the vehicle on jack stands.
Using a punch and a hammer, at the rear of the backing plate, knock out the lanced metal area near the star wheel assembly.
When knocking out the lanced metal area from the backing plate, the wheels must be removed and all of the metal pieces discarded.
Using the GM Brake Adjustment tool No. J-4735 or equivalent, insert it into the slot and engage the lowest possible tooth on the star wheel. Move the end of the brake tool downward to move the star wheel upward and expand the adjusting screw. Repeat this operation until the brakes lock the wheel.
Remove the metal tab from the backing plate. DO NOT allow it to fall into the drum
Use a brake adjusting spoon to turn the starwheel. A screwdriver just won't work that well
Insert a'small'screwdriver or piece of firm wire (coat hanger wire) into the adjusting slot and push the automatic adjuster lever out and free of the star wheel on the adjusting screw.
While holding the adjusting lever out of the way, engage the topmost tooth possible on the star wheel (with the brake tool). Move the end of the adjusting tool upward to move the adjusting screw star wheel downward and contact the adjusting screw. Back off the adjusting screw star wheel until the wheel spins freely with a minimum of drag. Keep track of the number of turns the star wheel is backed off.
Repeat this operation for the other side. When backing off the brakes on the other side, the adjusting lever must be backed off the same number of turns to prevent side-to-side brake pull.
Backing off the star wheel 12 notches (clicks) is usually enough to eliminate brake drag.
Repeat this operation on the other side of the rear brake system.
After the brakes are adjusted, install a rubber hole cover into the backing plate slot. To complete the brake adjustment operation, make several stops while backing the vehicle to equalize the wheels.
Road test the vehicle.
I am trying to adjust the Parking Drum Brake. Not rear drum brakes. The parking brake on this vehicle surrounds the drive shaft. Your answer is good for adjusting drum brakes on the wheels. Not what I am looking for. Thanks Greg
Maybe this might help. This is the adjustment for the transmission brake drum on a 1994 Chevy C3500. Maybe it is the same.
Adjusting the parking brake on models with rear discs