Air Brakes · Question #93

Why are slack adjusters checked?

A. To ensure brakes are within proper adjustment for safe stopping
B. To check air pressure
C. To check tire wear
D. To check coupling

Correct answer: A. To ensure brakes are within proper adjustment for safe stopping
Explanation: Out-of-adjustment slack adjusters are a leading cause of brake failure.

Why this question matters on the Air Brakes exam

This question is one of the 65 we have for the Air Brakes CDL knowledge test. The official AAMVA Commercial Driver License Manual chapter on Air Brakes covers exactly this topic, and most state DMV exams pull from the same chapter. Memorizing the right answer is fine for passing, but understanding the underlying rule is what keeps you safe on the road and out of trouble with FMCSA inspectors.

If this topic gave you trouble, take the full Air Brakes practice test to drill it across all the related questions. We recommend reading every explanation, even on the questions you got right, because the manual phrasing in the explanation often shows up word-for-word on the real exam.

Take the full Air Brakes practice test →