Footbrake adjustment.
As the master cylinder actuator is operated by air pressure from the footbrake valve, brake shoe travel is not reflected in brake pedal
movement. To provide an indication of brake shoe travel an indicator rod is incorporated in the dual actuator. The rod moves out of the
actuator housing to the same extent as the pushrod moves to operate the master , and when the red band on the indicator rod is fully exposed
the brake shoes require adjustment.
Before adjusting the brakes, check the hub bearings for slackness. If necessary, adjust the bearings.
Check also for excessive wear of the leading shoe linings. These can be examined through the inspection hole in each backplate.
To adjust, jack up each wheel in turn and proceed in the sequence given below. When adjusting the rear brakes, skotch the front wheels and
release the parking brake.
1 Charge the system to operating pressure.
2 Turn the shoe adjuster anti-clockwise until the drum is free to rotate.
3 Turn the front shoe adjuster clockwise (see fig N21) until the shoe is hard against the drum. Centralize the shoe by applying heavy pressure
to the brake pedal, then release the pedal.
4 Back off the adjuster until the shoe is just clear of the drum, ie so that the wheel rotates freely without the shoe rubbing.
5 Repeat operations 3 and 4 on the rear shoe adjuster.
Repeat for each wheel in turn.
6 Push in the indicator rod on the air actuator until it contacts the piston.
Illustration of brake adjusters:-
http://i24.photobucket.com/albums/c1...n/IMGP8511.jpg