Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Brake Shoe: Adjustments
These brakes have self-adjusting shoe mechanisms that assure correct lining-to-drum clearances at all times. The automatic adjusters operate only
when the brakes are applied as the vehicle is moving rearward or when the car comes to an uphill stop.
Although the brakes are self-adjusting, an initial adjustment is necessary after the brake shoes have been relined or replaced, or when the length of
the adjusting screw has been changed during some other service operation.
Frequent usage of an automatic transmission forward range to halt reverse vehicle motion may prevent the automatic adjusters from functioning,
thereby inducing low pedal heights. Should low pedal heights be encountered, it is recommended that numerous forward and reverse stops be
made until satisfactory pedal height is obtained.
If a low pedal condition cannot be corrected by making numerous reverse stops (provided the hydraulic system is free of air) it indicates that the
self-adjusting mechanism is not functioning. Therefore it will be necessary to remove the brake drum, clean, free up and lubricate the adjusting
mechanism. Then adjust the brakes, being sure the parking brake is fully released.
1. Using a suitable punch, knock out lanced area in backing plate or drum. If drum is installed on vehicle when this is done, remove drum and
clean brake compartment of all metal.
NOTICE: When adjustment is completed, a new hole cover must be installed in the backing plate.
2. Using suitable tool, turn brake adjusting screw to expand brake shoes at each wheel until wheel can just be turned by hand. Drag should be
equal on all wheels.
3. Back off adjusting screw at each wheel 30 notches.
4. If shoe still drags slightly on drum, back off adjusting screw an additional one or two notches.
5. When adjusting screw has been backed off approximately 12 notches, brakes should be free of drag. Heavy drag at this point indicates tight
parking brake cables.
6. Install adjusting hole cover in brake backing plate.
7. Check parking brake for proper adjustment.
