Brake Shoe: Adjustments

The rear drum brakes have self-adjusting shoe mechanisms that assure correct lining-to-drum clearances at all times. The automatic adjusters operate only when the service brakes are applied.
Although the brakes are self-adjusting, an initial adjustment is necessary after the brake shoes have been replaced, or when the length of the star wheel adjuster has been changed during some other service operation.

Fig. 2 Measuring Brake Drum Inside Diameter:

Fig. 3 Adjusting Brake Shoe Clearance:

1. Raise and support vehicle, then remove rear wheels and brake drums.
2. Check to make sure parking brake cable linkage and levers on secondary brake shoe are in ``free'' position.
3. Using brake shoe measuring tool No. J-21177 or equivalent, measure drum inside diameter, Fig. 2.
4. Turn brake adjusting screw to expand shoes to .050 inch less than diameter obtained on outside caliper portion of brake shoe measuring tool No. J-21177, Fig. 3.
5. Adjust parking brake. Whenever rear drum brakes are serviced, the parking brake linkage cable at the equalizer must always be readjusted to prevent possible damage to brake shoes.
6. Install brake drums, wheels and tires and lower vehicle to ground.
7. Drive vehicle and apply and release service brake 30-35 times with normal pedal force. Allow about one second between brake applications until satisfactory pedal height is obtained.