Pulsation in the brake pedal is usually corrected by servicing the front brakes. Service the rear brakes only if the problem persists. When the brake drums are removed, thoroughly clean and inspect them for cracks, scores, deep grooves, out-of-round and taper. Light scoring of the drum not exceeding 0.020 inch (0.51mm) in depth will not affect brake operation.
Inspect the brake drum for excessive taper and out-of-round. When measuring a drum for out-of-round, taper and wear, take measurements at the open and closed edges of the machined surfaces and at right angles to each other.
Removal & Installation
- Raise and safely support the vehicle with safety stands.
- Mark the relationship of the wheel to the axle flange to help maintain wheel balance after assembly.
- Remove the tire and wheel assembly.
- Mark the relationship of the brake drum to the axle flange.
If difficulty is encountered in removing the brake drum, the following steps may be of assistance.
- Make sure the parking brake is released.
- Back off the parking brake cable adjustment.
- Remove the access hole plug from the backing plate.
- Using a screwdriver, back off the adjusting screw.
- Install the access hole plug to prevent dirt or contamination from entering the drum brake assembly.
- Use a small amount of penetrating oil applied around the brake drum pilot hole.
- Carefully remove the brake drum from the vehicle.
After removing the brake drum, it should be checked for the following:
- Inspect for cracks and deep grooves.
- Inspect for out of round and taper.
- Inspecting for hot spots (black in color).
- Install the brake drum onto the vehicle aligning the reference marks on the axle flange.
- Install the tire and wheel assembly and hand-tighten the lug nuts.
- Carefully lower the vehicle, then tighten the lug nuts to 100 ft. lbs. (140 Nm).
- Road test the vehicle for proper brake operation.