NU Air Brake Test 2 2025

1. If there is a loss of pressure in the trailer supply line, you would expect the trailer brakes to be applied and
2. If the air pressure reaches 150 psi, the safety valve will open. Where is the safety valve located?
3. The low air warning device must activate by the time that tank air pressure falls to
4. Tank air pressure must not drop below _______ while the vehicle is in operation.
5. Minimum governor cut-out pressure is
6. When you test the system air-loss rate of a bus or straight truck, the maximum acceptable leakage rate is 3 psi within
7. Maximum governor cut-out pressure is
8. When you test the system air-loss rate, the maximum acceptable leakage rates per minute for a straight truck, a tractor pulling one trailer, and a tractor pulling two trailers are
9. With the engine idling at _________, air pressure must rise from 85 to 100 psi within two minutes.
10. Minimum governor cut-in pressure is
11. The governor cut-in pressure is normally _________ below the cut-out pressure.
12. Air pressure must rise _____________ with the engine idling at 600–900 rpm within 2 minutes.
13. Before starting the air brake practical test, make sure that air pressure is at least
14. The spring brakes will start to apply when the air pressure falls below
15. A tractor-trailer with one trailer will fail the air-loss rate test if the loss rate exceeds
16. The trailer air supply valve will close automatically if air pressure in the trailer supply line drops to
17. A tractor-trailer with two trailers will fail the air-loss rate test if the loss rate exceeds
18. Before beginning the air-loss tests of the air braking system, make sure that the air pressure has risen to
19. The air-loss rate test can be performed only when
20. Air compressors can either be driven by the engine belt and pulleys or
21. The spring brake test is passed if the vehicle
22. Different sizes of brake chamber on the same axle can cause
23. To test the air brakes, the vehicle should be parked
24. In a drum brake, the brake linings are attached to
25. Where is the air dryer located?
26. When draining the air tanks, you observe excessive oil coming out of the supply tank. Which of the following is most likely to be faulty?
27. You can usually make a normal stop by applying no more than
28. The coil spring in most spring parking brake chambers can exert a force of
29. Spring parking brakes typically require air pressures of at least _______ to completely release.
30. In the air service circuit, there is a double (two-way) check valve connected to the primary and secondary service tanks. What does this valve do?
31. Normally, who can adjust automatic slack adjusters?
32. Which statement is true of spring brakes?
33. Which colour coding is usually employed for the service line?
34. Why are there two service tanks in a modern air brake system?
35. What is the most frequent reason for placing a commercial vehicle out of service?
36. How can you check whether the trailer spring brakes have activated?
37. Which of these vehicles is most likely to be equipped with air brakes?
38. Where is the air pressure gauge for the service tanks?
39. Which colour is the trailer supply line?
40. What can cause the air pressure in the air brake system to drop?
41. How do you apply the parking brakes?
42. Your vehicle's air compressor is belt driven. How do you check for correct belt tension?
43. Which of these is not a part of a drum brake?
44. When brakes become overheated, they also become
45. What is a "glad hand"?
46. To bring a vehicle to a halt in the same distance when its weight has been doubled, the braking force should be what?
47. What powers the compressor in a vehicle's air brake system?
48. Where does a compressor pump the air in a vehicle's braking system?
49. What is leveraged to gain a mechanical advantage in a braking system?
50. What causes the wheels to stop spinning in a braking system?