AB Air Brake Test 12 2025

1. In a vehicle equipped with air brakes, what does the governor control?
2. Where is a relay valve usually installed?
3. What could be necessary to maintain adjustment in automatic brake adjusters?
4. Who must guarantee that brakes are correctly adjusted?
5. What is the one-way check valve's primary role in the brake system?
6. What determines the efficiency of the spring parking brake?
7. What is the purpose of an automatic limiting valve in an air brake system?
8. What is important to do before disassembling spring parking brake chambers?
9. How are spring brakes released?
10. How can some spring parking brakes be discharged mechanically?
11. Where can one typically find instructions on how to cage a spring parking brake?
12. What is the functionality count for the relay valve in an air brake system?
13. What is the end-point for the control line air in an air brake system?
14. What is the risk associated with disassembling a spring parking brake unit?
15. What component is fitted on the brake chamber to prevent debris from entering?
16. What is an essential step to safely cage the parking brake spring?
17. How is the caging of brakes accomplished?
18. What can be achieved by installing a control valve in the cab and a front brake limiting valve on the front axle?
19. When should you engage the spring parking brake after the brake drums have overheated?
20. During a pre-trip air brake inspection, you must ensure that the parking spring brake is not what?
21. What does the blue button on some air brake systems apply?
22. Besides being a parking brake, the spring parking brake system also functions as what?
23. What is referred to as compounding in the context of air brake systems?
24. Which of these statements is not true about how quickly the spring brakes will stop the vehicle?
25. What happens when the reservoir pressure drops to approximately 35 psi?
26. Who should disassemble a spring brake chamber?
27. Before a service brake application is made, where should parking brakes be positioned?
28. When a heated brake drum begins to cool and contract, what might the pressure from the spring parking brake cause it to do?
29. What does it mean to "cage" a spring in the context of air brake systems?
30. What position should the control valve be set in for driving on dry road surfaces?
31. What action allows reservoir air pressure to flow to the spring parking brake chambers?
32. When using an automatic limiting valve, brake applications between 40 psi and 60 psi are reduced to what?
33. What occurs to the parking brake spring during normal service brake operation?
34. Is the setup of spring parking brakes and their pipe arrangements consistent across all vehicle air brake systems?
35. Which of these statements is false about parking a vehicle with overheated brakes?
36. What component in the glad hands prevents air from leaking out?
37. What happens when the air pressure declines to a range between 20 and 45 psi?
38. How many air lines typically lead to the tractor protection valve?
39. What is the effect of opening the trailer supply valve?
40. What are the alternative names for the trailer supply valve?
41. What opens when the driver manually closes the trailer supply valve?
42. What is the result of disconnecting the supply line between the tractor and trailer while the trailer is still charged?
43. What alternative terminology is used to describe the application line?
44. If the driver accidentally uses the hand valve without a trailer being connected, what occurs?
45. What should be utilized to prevent dirt and water entry into the coupler and lines when the vehicle is used alone?
46. Why should you avoid using the hand valve for parking a trailer?
47. When the foot valve treadle is depressed by the driver, where is application air sent?
48. Where is a relay emergency valve typically installed?
49. In the context of tractor-trailer connection, what does "glad hands" refer to?
50. When joining the glad hands, how should the two gaskets and couplers be positioned relative to each other?
51. The tractor protection valve is generally situated where?