Drum Brake System: Service and Repair

Fig. 1 Releasing Self-adjuster Mechanism For Brake Drum Removal:

Fig. 2 Exploded View Of Brake Drum Assembly:

REMOVAL

1. Disconnect battery ground cable.
2. Raise and support vehicle.
3. Remove rear tire and wheel assembly.
4. Remove brake drum. Discard brake drum retaining clip.
5. Should difficulty be experienced in removal of the brake drum due to the action of the automatic self-adjuster mechanism, the self-adjuster may be released and brake drum removed, as follows:
a. Remove wheel cylinder attaching bolts.
b. Push wheel cylinder away from the brake backing plate to provide an access opening in the backing plate.
c. Insert a screwdriver through the backing plate and rotate self-adjuster cam to the released position, Fig. 1.
d. Remove brake drum.
e. Correctly position wheel cylinder and install attaching bolts. Torque bolts to specification.
6. Remove both brake shoe hold-down springs, Fig. 2. To prevent rotation during removal, hold each hold-down pin head with a suitable tool.
7. Pry lower end of the primary shoe from its position against the anchor.
8. Remove lower return spring.
9. Remove shoes and strut by passing the strut between the wheel cylinder and hub assembly.
10. Pull top of primary shoe away from the secondary shoe to disconnect strut from the secondary shoe.
11. Disconnect the parking brake cable from the secondary shoe lever.
12. Remove strut return spring from the secondary shoe.
13. Remove adjuster cam spring.
14. Pull primary shoe away from the strut while rotating the cam to the fully released position.
15. Remove the primary shoe spring.
16. Remove the primary shoe from the strut.

INSTALLATION

Before installing the brake shoes, ensure the wheel cylinder and wheel hub are tightened to specification.
1. Apply a light coating of grease supplied with the new brake shoes or high temperature grease D7AZ-19590-A, or equivalent, to support ledges where the brake shoes contact the backing plate.
2. Connect parking brake cable to the secondary shoe lever. To connect the cable, position the cable end through the lever and grip the cable end with locking type pliers, then push lever against the spring until it can be rotated over the cable. When properly installed, the plastic washer will be between the spring and lever.
3. Position the secondary shoe and install the hold-down spring.
4. Install the strut and cam assembly on the primary shoe.
5. Rotate the cam to the fully released position.
6. Install the adjuster cam spring.
7. Install the primary shoe spring.
8. Install the strut spring in the secondary shoe and then into the strut.
9. Place the strut on the parking brake lever and move the primary shoe toward the backing plate. The strut will then ``click'' into place over the parking brake lever and secondary shoe web.
10. Install the lower shoe spring with the longer leg on the secondary shoe.
11. Pry the lower end of the primary shoe into position against the anchor while holding the top of the shoe against the backing plate, in contact with the cylinder piston. Ensure not to damage the cylinder boot.
12. Install the primary shoe hold-down pin, spring and washer.
13. Ensure heel of each brake shoe is located behind the anchor plate. Check each brake component for proper installation.
14. If necessary, push adjuster cam to the released position.
15. Install brake drum(s).
16. Push brake pedal hard twice to set the self-adjuster cam position. The cam will make a ratcheting sound as it resets.
17. Adjust parking brake cable as necessary.