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QC Air Brake Test 4

  • Perfect for first-time and renewal commercial applicants, and those adding endorsements
  • Based on 2024 QC commercial driver's licence manual
  • Updated for July 2024
Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.
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QC commercial driver's licence
5 out of 5,
1 votes
What you need to know

Do you want to drive a truck in Quebec? To be a commercial driver in this province, you need a licence that is specific to the type of truck you want to drive. As a truck driver, you are a critical part of the transportation industry. The power and size of large trucks are awe-inspiring. Even while you’re driving safely, the smallest mistake can cause serious damage. Before you can get your commercial driver’s licence, you must pass both a written and practical test. The written test (also known as the Quebec commercial driver’s licence knowledge exam) has several multiple-choice questions. You must get at least an 80% to pass the knowledge examination. This 50-question practice test will help you to prepare for the Quebec (QC) Air Brake written test required to get your commercial driver’s licence. As you answer the questions on this test, we recommend checking each question’s explanation to gain further insight into the rule behind it. All questions on this test are based on the 2024 QC commercial driver’s guide. Good luck and drive safely!

What to expect on the official exam



correct answers to pass


passing score

List of questions (classic view)
  1. How often should the air tanks be drained?
  2. On a tractor-trailer, if the supply and service lines to the trailer are cross-connected, what may happen?
  3. How do you release DD3 safety actuator brakes?
  4. When you're going to tow a trailer, how can you tell if the trailer's antilock braking system (ABS) is working?
  5. Wedge brakes are
  6. The purpose of the tractor protection valve is
  7. To test the tractor protection valve, disconnect both trailer air lines and
  8. In a tractor-trailer, the connections between the tractor and the trailer include which of the following components?
  9. The hand valve control ("spike") applies
  10. Which brakes are more powerful, the spring brakes or the service brakes?
  11. Which of the following is NOT a part of a truck's braking system?
  12. A tractor-trailer's braking system supplies compressed air to which trailer brakes FIRST?
  13. An S-cam is found in
  14. When coupling a tractor to a trailer, how many air lines do you have to connect?
  15. If there is a loss of air to the service brakes in a trailer with a spring brake priority system, how can you brake the trailer to a stop?
  16. In a trailer with a spring brake priority system, compressed air is supplied to which brakes FIRST?
  17. How many air lines must be connected to a DD3 safety actuator brake chamber?
  18. The tractor protection valve closes to stop the flow of compressed air to
  19. To uncouple your tractor from the trailer, how should you set the trailer air supply valve?
  20. Which of the following is not a component of a wedge brake?
  21. How often should you check brake chamber pushrod travel?
  22. Which of the following is a part of a disc brake?
  23. In an air braking system, which of the following is not commonly part of a disc brake?
  24. Which of the following are helpful in reducing heat in the air brake system?
  25. Which of the following can affect pushrod stroke?
  26. If you find a major defect in the air brake system, you should
  27. How can you determine applied pushrod stroke?
  28. Which is least likely to cause brake drums to overheat?
  29. When must full braking capability be available?
  30. In Canada, antilock braking systems (ABS) have been mandatory on all trucks and buses over 4,560 kg that have been manufactured since
  31. Which of the following is the best way to inspect an air compressor?
  32. When can you adjust automatic slack adjusters?
  33. If the outer layer of an air line is damaged, but the inner tube is still OK, what should you do?
  34. To make sure the air tanks are securely attached to your vehicle, you should
  35. Before inspecting your air brakes, you should
  36. Your vehicle passes the tug test of the parking brakes if
  37. If the brake chambers on opposite sides of an axle are of different sizes, the result may be
  38. To check the brake chambers for leaks, you should
  39. in a drum brake, the brake lining is fastened to
  40. Compared with the service tanks, how much moisture should the supply tank discharge?
  41. What function does the hand brake control serve?
  42. Why is it crucial to drain the reservoirs after operating your vehicle during winter, while the vehicle is still warm?
  43. How is the first reservoir commonly referred to?
  44. What is not included in all brake systems?
  45. How many kinds of low air pressure warning devices does a vehicle typically have?
  46. At what point is an emergency brake automatically triggered during a situation where the air pressure in the service brake system decreases beyond a certain level?
  47. What occurs once air is introduced into the brake chambers?
  48. Why do air brake lines contain relay valves?
  49. Which of these statements about braking power is FALSE? The generated braking power depends on a combination of factors, including
  50. Do supplemental brake systems offer enough stopping power to halt your vehicle?