CDL Practice Test - Driver's License Test Sample Questions2

CDL Practice Test - Air Brakes Test

CDL Practice Test - AIR BRAKE TEST Sample Questions

1. The air compressor governor controls:
a. the speed of the air compressor.
b. air pressure applied to the brakes.
c. when the compressor will pump air into the storage tanks.

2. Modern air brake systems combine three different systems. They are the service brake, the parking brake and the:
a. emergency brakes.
b. foot brakes.
c. S-cam brakes.

3. If the air compressor develops a leak, what keeps the air in the tank?
a. the tractor protection valve.
b. the emergency relay valve.
c. the one way check valve.

4. Vehicles with air brakes must have:
a. at least two air tanks.
b. an air pressure gauge, to show the pressure available for braking.
c. an air use gauge, to show air used by the brake chambers for braking.

5. A straight truck or bus air brake system cannot leak more than ____ per minute with the engine off and the brakes released.
a. 1 psi
b. 2 psi
c. 3 psi

6. During normal driving, parking and emergency brakes are usually held back by:
a. air pressure.
b. spring pressure.
c. centrifugal force.

7. To check the free play in the manual slack adjusters, you need to:
a. stop on level ground and apply the parking brake.
b. park on level ground, chock the wheels and release the parking brake.
c. apply the service brake by hand and watch the slack adjusters move.

8. The effectiveness of the spring brakes:
a. has nothing to do with the condition of the service brake.
b. can only be tested by highly trained brake service people.
c. depends on the adjustments of the service brakes.

9. Which of the following makes total stopping distance longer for air brakes than hydraulic?
a. perception distance.
b. reaction distance.
c. brake lag.

10. The first thing to do when a low pressure warning comes on is:
a. stop and safely park as soon as possible.
b. upshift.
c. open the air supply valve.

11. Air braking takes more time than hydraulic braking because air brakes:
a. use different brake drums.
b. need to have air flow through the lines to work.
c. require heavier return springs.

12. Experts do not recommend fanning (on-again off-again braking) for long downhill runs because:
a. air usage is less when fanning.
b. brake linings do not get hot when fanning.
c. the short time off the brakes does not allow the brakes to cool.

13. Oil and water that collects in air tanks can make brakes fail. If you do not have automatic tank drains, when should you drain the air tanks?
a. every other day.
b. every day.
c. every week.

14. the driver must be able to see a warning that is given when air pressure in the service air tanks falls below:
a. 40 psi.
b. 50 psi.
c. 60 psi.

15. An air brake system safety relief valve opens at about:
a. 20 to 45 psi.
b. 120 psi.
c. 150 psi.

16. When some air brakes in the system are doing more work than others:
a. those brakes will develop more heat.
b. vehicle handling will be effected.
c. all the above.

17. Your safety relief valve has opened several times. This means______.
a. the system is working properly.
b. your pressure is probably low.
c. the system needs immediate attention.

18. At what air pressure should the low air warning alarm come on?
a. 45 psi.
b. 25 psi.
c. must come on by 60 psi.

19. With the brakes released on a single vehicle, what is the allowable air lose?
a. 4 psi.
b. 3 psi.
c. 2 psi.

20. To test the air compressor on a dual air brake vehicle, run the engine at a fast idle to charge the air the system. Your gauges should show your___________.
a. pressure builds from 85 to 100 psi with-in three minutes.
b. your pressure builds from 85 to 100 psi with-in 45 seconds.
c. the compressor cuts out by 75 psi.

21. Spring brakes are applied by____________?
a. air pressure.
b. electrical current.
c. a means other than air, electrical or hydraulic.

22. Most large vehicles with air brakes have spring brakes which_____.
a. are part of the parking brake systems operation only.
b. are part of the service brake system only.
c. are part of both the parking and emergency brakes.

23. What color is the parking control knob on the dash of the vehicle?
a. red.
b. green.
c. yellow.

24. What would cause all of the air brake systems on a vehicle to have poor braking power.
a. low hydraulic fluid.
b. brakes being out of adjustment.
c. a broken air line.

25. If a low air pressure warning comes on what should you do?
a. pull off the road as soon as it is safe to do so.
b. you can safely continue until you get to the next service center.
c. turn it off so that it will not distract you.

26. "Cut – in" pressure is normally set to ______ psi.
a. 100.
b. 125.
c. 150.

27. How often should you drain your air tanks?
a. Monthly.
b. Ever 3 months or 3000 miles.
c. Daily.

28. Which of the following is not an air brake subsystem?
a. Spring brake system.
b. Service brake system.
c. Parking brake system.

29. What is a "Wig Wag"?
a. A mechanical arm that signals low air pressure.
b. A spring mount for hair pieces.
c. Part of the stop light system.

30. "Cut – out" pressure is normally set to ____ psi.
a. 100.
b. 125.
c. 150.

31. Front brake limiting valves are found on:
a. Older vehicles made before 1975.
b. New import vehicles only.
c. School buses.

32. To reduce the risk of ice, some air systems incorporate:
a. An air compressor heating unit.
b. An air tank warmer unit.
c. An alcohol evaporator.

33. At 55 MHP brake lag ( on air brake vehicles) can add an additional ____ feet to your overall stopping distance.
a. 32 feet.
b. 64 feet.
c. 100 feet.

34. When testing service brakes you should look for:
a. Pulling to either side.
b. Delayed stopping action.
c. All the above.

35. In newer vehicles, parking brakes are applied using:
a. A blue flip switch.
b. A yellow and red lever.
c. A yellow diamond shaped push-pull knob.
For the next ten questions us the air brake drawing

36. Identify item D.
a. Push rod.
b. Pitman.
c. Neither of the above.

37. Identify item H
a. Push rod.
b. Slack adjuster.
c. Drag link.

38. Identify item C
a. Brake cam.
b. Adjusting nut.
c. Return spring.

39. Identify item E
a. Brake cam.
b. Cam roller.
c. Drag link.

40. Identify item A
a. Axle.
b. Cam roller.
c. Brake drum.

41. Identify item B
a. Brake chamber.
b. Brake shoes.
c. Brake drum.

42. Identify item J
a. Brake chamber.
b. Brake roller.
c. Brake cam.

43. Identify item F
a. Return spring.
b. Adjusting nut.
c. S cam

44. Identify item I
a. Adjusting nut.
b. Axle.
c. Push rod.

45. Identify item G
a. Adjusting nut.
b. Axle.
c. Brake cam.


Answers to above Air Brakes Test sample questions

1. c
2. a
3. c
4. b
5. b
6. a
7. b
8. c
9. c
10. a
11. b
12. c
13. b
14. c
15. c
16. c
17. c
18. c
19. c
20. b
21. c
22. c
23. c
24. b
25. a.
26. a
27. c
28. a
29. a
30. b
31. a
32. c
33. a
34. c
35. c
36. c
37. b
38. c
39. b
40. a
41. c
42. a
43. c
44. c
45. a

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