Massachusetts CDL — Air Brakes Practice Test

The Massachusetts CDL — Air Brakes knowledge test has 25 questions; you need 20 correct (80%) to pass.

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25 questions · pass with 20 correct. You get instant feedback and an explanation after every answer.

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The full-length test, with feedback and an explanation after every answer.

Massachusetts CDL — Air Brakes practice tests

10 full-length practice tests, each with 25 questions and a pass mark of 20, like the real test. You see the answers and explanations after you grade.

Test 1
25 questions · pass with 20
How are your brake lights switched on when you apply the air brakes?
Test 2
25 questions · pass with 20
How often should tanks with manually operated drain valves be emptied?
Test 3
25 questions · pass with 20
What does an alcohol evaporator do in an air brake system?
Test 4
25 questions · pass with 20
While you are driving normally, what keeps the powerful springs of the spring brakes from applying the brakes?
Test 5
25 questions · pass with 20
You have just pushed through deep standing water and your brakes are soaked. How does the manual say to get them working again?
Test 6
25 questions · pass with 20
What most directly causes brake fade on a long downgrade?
Test 7
25 questions · pass with 20
When checking manual slack adjusters on s-cam brakes, about how much movement where the push rod attaches suggests they need adjustment?
Test 8
25 questions · pass with 20
What is the role of the service brake system?
Test 9
25 questions · pass with 20
With the system fully charged, the engine off, and the parking brake released, the air loss on a single vehicle should stay under how much per minute?
Test 10
25 questions · pass with 20
What does the manual say about braking with the front wheels?