When adjusting a manual slack adjuster, how can you tell whether you are turning the adjusting bolt in the correct direction?
- The cam will rotate in the same direction as if the brakes were being released.
- The slack adjuster will pull the pushrod out of the chamber.
- The slack adjuster will push the pushrod into the chamber.
- The cam will rotate in the same direction as if the brakes were being applied. ✓
Answer: D. The cam will rotate in the same direction as if the brakes were being applied.
Turn the adjusting bolt while watching the camshaft; if you are turning the correct way, the cam rotates in the same direction it would when the brakes are applied.
Why this is the answer
The handbook says to depress the locking sleeve and turn the adjusting bolt while watching the end of the camshaft. It states that the camshaft moves slightly as you turn the bolt, and the correct direction is the one where the cam turns the same way it would if the brakes were being applied. That is the indicator to use so you know you are tightening the adjustment rather than loosening it.
Why the other answers are wrong
- A. The cam will rotate in the same direction as if the brakes were being released. — A cam rotating as if the brakes were being released is the opposite of the handbook's correct indicator, so it would mean you are not tightening the adjustment.
- B. The slack adjuster will pull the pushrod out of the chamber. — If the slack adjuster pulls the pushrod out of the chamber, the handbook says to stop because the adjusting bolt is being turned in the wrong direction.
- C. The slack adjuster will push the pushrod into the chamber. — A pushrod going into the chamber is described as a sign that the earlier slack adjustment was done incorrectly, not as the sign that you are turning the bolt the right way.
Remember it
Watch the cam, not the pushrod: correct tightening turns the cam the same way the brakes apply.