All drivers should be trained to make brake adjustments. If a driver must adjust the brakes on their vehicle (at a mandatory brake check sign for example), the following steps are recommended for ‘S’ cam brakes:

1. Block the wheels, release spring brakes and shut off the engine, leaving it in low gear. Check the push rod travel by pulling on a slack adjuster by hand or with a pry bar. If on common brake chamber, slack (push rod travel) exceeds 3/4 inch brake adjustment is required.

CAUTION: A strong physical pull is necessary to move all the slack out of the travel.

2. After determining that brake adjustment is necessary:
   1. Use a proper wrench to disengage the external locking device (if so equipped) from the adjustment bolt of the slack adjuster.
   2. Turn the adjustment bolt until the lining contracts the drum. If possible, visually check to see that the brake linings are in contact with the brake drum.
   3. When turning the adjustment bolt on the slack adjuster, the spline on the S cam shaft should turn in the same direction as if a brake application were being made.
   4. Back the adjustment bolt about 1/4 to 1/2 of a turn. This should result in proper adjustment.
   5. Now re-check for free play of slack adjuster travel. The travel should now be between 1/2 and 3/4 of an inch. If travel is checked by watching the push rod while someone makes a brake application, travel should not exceed 1-1/2 inches.