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FREE NL Air Brake Practice Test 1 2025

Based on the 2025 NL CDL manual
Questions: 35
Mistakes allowed: 7
Passing score: 80%
Ensuring the accuracy and quality of our practice tests is paramount. Learn more about our rigorous standards in our Commitment to Accuracy article.

Welcome to the first of our nine Newfoundland and Labrador Air Brakes Practice Tests! We designed these practice tests to help you pass the official Air Brakes knowledge test on your first try. These practice tests can also help you ace air brake questions on the official Class 1 knowledge test.

All applicants for a commercial driver’s licence must have held a Class 5 driver’s licence for at least one year and submitted a routine medical form. Then you must pass a general knowledge test on the theory of commercial driving. Except for Class 1, if you’ll be applying for an Air Brake Endorsement, you must also complete an approved Air Brake course and pass a separate Air Brake knowledge test. For Class 1, this endorsement is mandatory. The general knowledge test for Class 1 includes test questions on air brakes, so a separate air brake knowledge test is not required. The air brake test questions are based on the official NL Air Brake Manual.

Passing the general knowledge test will entitle you to a commercial learner’s permit, allowing you to practice commercial driving under supervision.

When you’re ready, you can schedule a road test for your commercial driver’s licence. However, if you’re applying for a Class 1 licence, you must complete Mandatory Entry-Level Training (MELT) before taking the road test. MELT for Class 1 includes training in air brakes. You must take the road test in a vehicle that’s representative of the class of licence you’re applying for. For a Class 1 licence or another class of commercial licence with a planned air brake endorsement, you must take the road test in a vehicle equipped with air brakes.

Unfortunately, neither reading the official Air Brake Manual nor taking a short Air Brake course can ensure you’ll pass the Air Brakes knowledge test on your first try. But our knowledge test preparation program does!

This is the first of our nine Newfoundland and Labrador Air Brakes Practice Tests. It includes 35 multiple-choice questions on air brakes. All questions are up to date as of May 2025 and based on the official Air Brake Manual.

If you get stuck on a practice question, you can ask our AI Assistant to discuss the question further, give you a hint, or answer your own questions about commercial driving. If you still miss the question, you’ll be shown the correct answer and an explanation.

5 out of 5 • 3 votes.
Based on 2025 NL commercial driver's license manual
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List of questions (classic view)
  1. Should you pump (keep pressing and releasing) air brakes?
  2. It is important to keep compressed air as dry as possible because
  3. What does the low air pressure warning device warn you about?
  4. If the low air pressure warning signal comes on, what should you do?
  5. The effectiveness of the spring brakes for emergencies or parking
  6. During normal driving, what keeps the spring brakes released?
  7. Assuming good traction and constant vehicle weight, if you double your speed, your vehicle's braking distance will be
  8. If drum brakes overheat, the vehicle's stopping distance will increase. What is the reason for this?
  9. Air braking systems tend to react slower than hydraulic braking systems because
  10. While travelling downhill, you notice that each time you want to brake, you must press the brake pedal farther down than the last time to achieve the same braking force. What could be causing this?
  11. The maximum air pressure available for braking is determined by
  12. The foot (treadle) valve
  13. Which of the following can impair braking effectiveness?
  14. After you apply the service brakes, what happens to that compressed air?
  15. What does an alcohol evaporator do?
  16. When you test the system air-loss rate, the maximum acceptable leakage rates per minute after the initial drop are
  17. You're driving a vehicle equipped with a dual air brake system. The low air pressure warning signal comes on, but one system still has normal pressure. What should you do?
  18. How should you test your vehicle's low air pressure warning signal?
  19. An application pressure gauge shows the air pressure
  20. All vehicles equipped with air brakes must have
  21. What is the colour coding that is often used for the supply and service lines to the trailer?
  22. The hand valve of a tractor-trailer
  23. In a vehicle equipped with air brakes, what does the governor control?
  24. Polarized gladhands on a tractor
  25. ln vehicles with three dash-mounted push-pull valve knobs, how are the valve knobs usually coloured?
  26. Which of the following are major components of the air supply circuit?
  27. Wedge brakes are designed to be
  28. Where are the air brake chambers located?
  29. What does an ABS system do?
  30. When you are going at twice the speed, your service brakes will need to work _________ to stop your vehicle.
  31. Which of these significantly decreases the braking force produced at the wheel?
  32. Which type of trailer can be towed before the service tanks are full?
  33. In determining how well your air brake system works, which is NOT a significant factor?
  34. In large commercial vehicles, most air brake systems use automatic valves to
  35. Where are a vehicle's air tanks located?
  36. What is the "cut-in" level?
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