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Practice test 6 of 10

Massachusetts CDL — Air Brakes Practice Test 6

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

This practice test follows that format: 25 questions, pass with 20 correct. Answer every page, then grade it to see the answers and explanations.

Questions 1–10 of 25

  1. 1.What most directly causes brake fade on a long downgrade?
  2. 2.Which foundation brake is the most common on air-brake vehicles?
  3. 3.What does a supply pressure gauge tell you?
  4. 4.At about what pressure does the governor "cut in" and let the compressor pump again?
  5. 5.The low-air-pressure warning must come on before tank pressure drops below what level?
  6. 6.You notice you must apply more and more pressure to hold the same speed. What does that usually mean, and what should you do?
  7. 7.Your tractor has ABS but the trailer behind it does not, and during a hard stop the trailer begins to swing out. What does the manual advise?
  8. 8.What must you always do before leaving your vehicle unattended?
  9. 9.According to the manual, which defect turns up most often during roadside inspections?
  10. 10.Why is it dangerous to keep rolling in a heavily loaded truck until the spring brakes grab on their own?

0 of 25 answered