North Carolina CDL — Air Brakes Practice Test

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

Or take one of 10 full-length practice tests

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

Choose your level

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

North Carolina 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
Why is it important to drain the air storage tanks?
Test 2
25 questions · pass with 20
In a dual air brake system, what are the two circuits called?
Test 3
25 questions · pass with 20
What is a dual air brake system?
Test 4
25 questions · pass with 20
What is the purpose of a modulating control valve?
Test 5
25 questions · pass with 20
Even if the air compressor quit while you were driving, why can you still make several brake applications?
Test 6
25 questions · pass with 20
When inspecting brake drums, how large a crack is still within limits?
Test 7
25 questions · pass with 20
While you drive, what holds the powerful spring brakes in the released position?
Test 8
25 questions · pass with 20
When the low-air warning first lights up while driving, what should you do?
Test 9
25 questions · pass with 20
Which type of foundation brake is the most common on air-brake vehicles?
Test 10
25 questions · pass with 20
While you drive, what holds the powerful spring brakes in the released position?