Air Brakes Test Sect. 3

Front 1

1. Emergency stab braking is when you

Back 1

Brake as hard as you can, release the brakes when the wheels lock, and put on the brakes again when the wheels start rolling

Front 2

2. If air pressure does NOT build up to normal within the correct amount of time, then

Back 2

Your air pressure may drop too low during driving, requiring an emergency stop.

Front 3

3. Which of these is NOT a proper time to apply the parking brakes?

Back 3

If the brakes are very hot (e.g. after just coming down a steep grade)

Front 4

4. Excessive use of the service brakes results in overheating which can lead to

Back 4

Expansion of the brake drums

Front 5

5. The proper method of braking when going down long and or steep grades, after selecting the proper grade, is to brake until your speed is about ___ miles per hour below your "safe" speed, then release your brakes.

Back 5

Five

Front 6

6. Under normal conditions, in order to engage the parking brakes, the driver must first

Back 6

Let the air out of the air brake system.

Front 7

7. Total stopping distance for air brakes is longer than that for hydraulic brakes due to ___ distance.

Back 7

Brake lag

Front 8

8. If you must make and emergency stop, you should brake so you

Back 8

Can steer Nd so your vehicle stays in a straight line

Front 9

9. If your truck or bus has dual parking control valves, you can use pressure from a separate tank to

Back 9

Release the spring emergency/parking brakes to move a short distance

Front 10

10. To check the free play of manuel slack adjusters in S-cam brakes, you should park on

Back 10

Level ground, chock the wheels and turn off the parking brakes.

Front 11

11. A straight truck or bus air brake system should not leak at a rate of more than ___ per minute with the engine off and the brakes released.

Back 11

2 PSI

Front 12

12. The air compressor governor controls:

When the air is ___ into the air tanks

Back 12

Pumped

Front 13

13. The parking or emergency brake of trucks and buses can only be legally held on by

Back 13

Spring pressure

Front 14

14. The brake pedal in an air brake system

Back 14

Controls the air pressure applied to put on the brakes.

Front 15

15. Some air brake systems have an alcohol evaporator. What may happen if you don't keep the unit filled with alcohol?

Back 15

Ice may form in the air storage tanks Nd cause the brakes to fail

Front 16

16. The brake system that applies and releases the brakes when the driver uses the brake pedal is the ___ brake system..

Back 16

Service

Front 17

17. Before driving a truck or bus with a dual air brake system, the pressure in each system should be at least ___

Back 17

100 PSI

Front 18

18. Your truck or bus has a dual air brake system. If a low pressure warning comes on for only one system, what should you do?

Back 18

Stop right away and safely park. Continue only after the system is fixed

Front 19

19. How should you check that your service brakes are working properly?

Back 19

Wait for normal air pressure, release the parking brake, move the truck forward slowly and apply the brakes firmly using the brake pedal.

Front 20

20. You should know that your brakes are fading when:

Back 20

You have to push harder on the brake pedal to control your speed on a downgrade.

Front 21

21. If the spring brakes are on, when should you push the brake pedal?

Back 21

NEVER

Front 22

22. The driver must be able to see a low pressure warning which comes on before pressure in the service air tanks falls below ___ PSI.

Back 22

55

Front 23

23. The most common type of foundation brake found on heavy vehicles is the

Back 23

S-CAM drum

Front 24

24. If your truck has a dual air system and one of these systems is low on pressure

Back 24

Either the front or rear brakes will not be fully operational.

Front 25

25. In air brake vehicles, the parking brakes should be used

Back 25

Any time the vehicle is parked

Front 26

26. The stop light switch

Back 26

Turns on the brake lights to warn drives drivers behind you.

Front 27

27. For air brake systems in good condition, the air compressor should start pumping at about ___ PSI

Back 27

100

Front 28

28. The air loss for a straight truck or bus with the engine off and the brakes on should not be more than

Back 28

3 PSI IN ONE MINUTE

Front 29

29. The braking power of the spring brakes

Back 29

Depends on the service brakes being in adjustment

Front 30

30. How should you check that the spring brakes comes on when the air pressure in the system drops below a certain level?

Back 30

Chock the wheels, apply the parking brake, shut the engine off and pump the brake pedal to reduce air tank pressure.

Front 31

31. If you are driving down a steep downgrade and have reached your "safe" speed of 40 mph, you would apply the service brakes until your speed drops ___ mph.

Back 31

35

Front 32

32. The air brake lag distance at 55 mph on dry pavement adds about ___ feet to your stopping distance

Back 32

32

Front 33

33. Repeatedly pressing and releasing (fanning) the brake pedal may result in

Back 33

The loss of brake air pressure.

Front 34

34. Emergency controlled braking is when you

Back 34

Apply the brake as hard as you can without locking the wheels.

Front 35

35. If your truck's air compressor has its own oil supply, when should you check the oil level?

Back 35

Before driving.

Front 36

36. If your vehicle has an alcohol evaporator, it is there to

Back 36

Reduce the risk of ice in air brake valves in cold weather.

Front 37

37. The application pressure gauge shows how much air pressure you

Back 37

Are applying to the brakes.

Front 38

38. The most important thing to do when a low air pressure warning comes on is

Back 38

Stop and safely park as soon as possible.

Front 39

39. Your vehicle has a dual air brake system. If a low pressure warning comes on for the secondary system, you should

Back 39

Bring the vehicle to a safe stop and continue only when the system is fixed

Front 40

40. If your truck has a properly functioning dual air brake system and minimum size air tanks, the air pressure should build from 85 to 100 PSI within ___ seconds.

Back 40

45

Front 41

41. When the brakes are applied, the brake shoes ( or linings) are pressed against the

Back 41

Brake drum or disc

Front 42

42. Under ideal conditions, a truck with air brakes going 55 mph would require stopping distance of

Back 42

More than 30 feet

Front 43

43. The use of air brakes on a long and/or steep downgrade under normal conditions is only a supplement to

Back 43

The braking effect of the engine

Front 44

44. The air compressor should stop pumping at about ___ PSI

Back 44

125

Front 45

45. All air brake equipped vehicles have

Back 45

An air supply pressure gauge

Front 46

46. During normal driving, sping brakes are usually held back by

Back 46

Air pressure.

Front 47

47. The safety valve is usually set to automatically reduce pressure at

Back 47

150 PSI

Front 48

48. Air brakes take more time than hydraulic braking because air

Back 48

Takes more time to flow through the lines than hydraulic

Front 49

49. Why drain water from compressed air tanks?

Back 49

Water can freeze in cold weather and cause brake failure.

Front 50

50. It is not safe to drive a vehicle that has brake drums (or discs) with cracks or that are thinner than manufacturer's specifications. Generally this will be

Back 50

1/4 inch.

Front 51

51. The modulating valve allows you to control the

Back 51

Amount of pressure in the brake system.