Air Brakes

Question 1

1) Which of the following about antilock braking systems is true?

Answer 1

ABS changes the way you brake in Emergencies.

Question 2

2) In air brake vehicles, the parking brakes should be used:

Answer 2

Anytime the vehicle is parked.

Question 3

3)If your antilock braking system is not working, you should:

Answer 3

Drive normally, but get the system serviced soon.

Question 4

4)
Excessive use of the service brakes results in overheating, which can lead to:

Answer 4

Expansion of the brake drums.

Question 5

5)
Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system

Answer 5

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

Question 6

6) The air compressor should stop pumping prior to reaching a — psi.

Answer 6

140

Question 7

7)
The use of air brakes on a downgrade is only a supplement to the:

Answer 7

Braking effect of the engine

Question 8

8)
Your truck has properly functioning dual air brake system and minimum size air tanks. The air pressure should build from 85-100 psi within
seconds.

Answer 8

45

Question 9

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

Answer 9

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

Question 10

10) The proper method of braking when going down long and/or steep grades after selecting the proper gear is to brake until your speed is about__ miles per hour below your “safe” speed, and then release your brakes.

Answer 10

5

Question 11

It is not safe to drive a vehicle that has brake drums (or discs) with cracks or that are thinner than the manufacturer’s specifications, generally this will be __ inch.

Answer 11

1/4

Question 12

12)
A supply pressure gauge tells you how much pressure is in the:

Answer 12

Air tanks

Question 13

13)
Air braking takes more time than hydraulic braking because air:

Answer 13

Takes more time to flow through the lines than hydraulic fluid.

Question 14

14)
During normal driving, spring brakes are usually held back by:

Answer 14

Air pressure

Question 15

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

Answer 15

Ice may form in the air storage tanks and cause the brakes to fall

Question 16

16)
The brake system that applies and releases the brakes when the driver uses the brake pedal is the__ system brake

Answer 16

Service

Question 17

17)
In air brake vehicles, the parking brakes should be used:

Answer 17

Any tme the vehicle is parked

Question 18

18)
Excessive heat in the brakes can cause the:

Answer 18

Brakes to fade or fall

Question 19

19) To test air service brakes, you should:

Answer 19

Brake firmly when slowly moving forwards

Question 20

20)
You should know your brakes are fading when:

Answer 20

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

Question 21

21)
The air brake system for a straight truck or bus should not leak at a rate of more than __ psi per minute with the engine off and the brakes released.

Answer 21

2

Question 22

22) - The braking power of the spring brakes:

Answer 22

Depends on the service brakes being in adjustment.

Question 23

23)
If your truck has a dual air brake system and one of the systems is low on pressure:

Answer 23

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

Question 24

24)
The parking or emergency brakes of trucks and buses can be legally held on by ___ pressure

Answer 24

Spring pressure

Question 25

25) Modern air brake systems are three different systems combined together. They are the service, parking, and the ___ brakes.

Answer 25

Emergency

Question 26

26) The air supply pressure gauge shows how much pressure:

Answer 26

Is in the air tanks

Question 27

27) If you must make an emergency stop, brake so you:

Answer 27

Can steer and your vehicle stays in a straight line.

Question 28

28) If your vehicle has an alcohol evaporator, it is there to:

Answer 28

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

Question 29

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

Answer 29

32

Question 30

30) The spring brakes used on tractors and straight trucks will bring your truck to a stop when the air pressure drops Below ___ psi.

Answer 30

20

Question 31

31) When you apply the brakes, the brake shoes/linings are pressed against the:

Answer 31

Brake drum

Question 32

32) The use of air brakes on a downgrade is only a supplement to the:

Answer 32

Braking effect of the engine

Question 33

33) Why should you drain water from compressed air tanks?

Answer 33

Water can freeze in cold weather and cause brake failure

Question 34

34) Repeatedly pressing and releasing (fanning) the brake pedal may result in:

Answer 34

The loss of brake air pressure.

Question 35

35) The parking or emergency brakes of trucks and buses can be legally held on by ___ pressure.

Answer 35

Spring

Question 36

36) The air compressor governor controls:

Answer 36

When air is pumped into the air storage tanks

Question 37

37) The most common type of foundation brake found on heavy vehicies is the:

Answer 37

S-cam drum

Question 38

38) You are on a steep downgrade and have reached your "safe" speed of 40 mph. You would apply the service brakes until your speed drops to___ mph

Answer 38

35

Question 39

39) You should know brakes are fading when:

Answer 39

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

Question 40

40) Under normal conditions, to engage the parking brake the driver must first:

Answer 40

Let the air out of the spring brakes.

Question 41

41) If you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage air tanks?

Answer 41

At the end of each day for driving.

Question 42

42) When is it OK to leave your truck unattended without applying the parking brake or chocking the wheels?

Answer 42

Never

Question 43

43) What is the first thing you should do when a low air pressure warning comes on?

Answer 43

Stop and safely park as soon as possible.

Question 44

44) The brake pedal in an air brake system:

Answer 44

Controls the air pressure applied to put on the brakes.

Question 45

45) Before driving a truck or bus with a dual air brake system, the pressure in each system should be at least_____ psi

Answer 45

100

Question 46

46) Moder air brake systems are three different systems combined together. They are the service, parking, and the ____brakes.

Answer 46

Emergency

Question 47

47) For air brake systems in good condition, the air compressor should start pumping at about ___ psi.

Answer 47

100

Question 48

48) How should you check that the spring brakes come on when air pressure in the system drops below a certain level?

Answer 48

Park on level ground, chock the wheels, release the parking brake when you have enough air pressure, shut the engine off, and repeatedly press and release the brake pedal.

Question 49

49) The safety valve is set to automatically reduce pressure at __ psi.

Answer 49

150

Question 50

50) Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to ___ distance.

Answer 50

Brake lag

Question 51

51) Air braking takes more time than hydraulic braking because air:

Answer 51

Takes more time to flow through the lines than hydraulic fluid.

Question 52

52) How should you check that your service brakes are working properly?

Answer 52

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

Question 53

53) The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:

Answer 53

3 psi in one minute

Question 54

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

Answer 54

5

Question 55

55) All air brake equipped vehicles have:

Answer 55

An air supply pressure gauge.

Question 56

56) The driver must be able to see a warning before air pressure in the service air tanks falls below ___psi.

Answer 56

55

Question 57

57) If spring brakes are on, when should you push the brake pedal?

Answer 57

Never

Question 58

58) Emergency controlled braking is when you:

Answer 58

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

Question 59

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

Answer 59

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

Question 60

60) When you apply the brakes, the brake shoes/linings re pressed against the:

Answer 60

Brake drum

Question 61

61) The most important thing to do when a low air pressure warning comes on is:

Answer 61

Stop and safely park as soon as possible.

Question 62

62) If your vehicle has an alcohol evaporator, every day during cold weather you should:

Answer 62

Check and fill the alcohol level.

Question 63

63) Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to ____distance

Answer 63

Brake lag

Question 64

64) When is it OK to leave your truck unattended without applying the parking brake or chocking the wheels?

Answer 64

Never

Question 65

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

Answer 65

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

Question 66

66) The modulating control valve allows you to control the:

Answer 66

Spring brakes

Question 67

67) The S-cam:

Answer 67

Forces the brake shoes against the inside of the brake drum

Question 68

68) What is emergency stab braking?

Answer 68

Brake hard, release the brakes when the wheels lock, and reapply the brakes when the wheels start rolling.

Question 69

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

Answer 69

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

Question 70

70) Which of these is not a proper time to apply the parking breaks?

Answer 70

When your brakes are very hot.

Question 71

71) The application pressure gauge shows how much air pressure you:

Answer 71

Are applying to the brakes.

Question 72

72) The air brake lag distance at 55 mph on dry pavement adds about___ feet to your stopping distance.

Answer 72

32

Question 73

73) If pressure does not build up fast enough within the correct amount of time:

Answer 73

Your air pressure may drop too low during driving.

Question 74

74) The stop light switch:

Answer 74

Turns on the brake lights to warn drivers behind you.

Question 75

75) Why should you drain water from compressed air tanks?

Answer 75

Water can freeze in cold weather and cause brake failure.

Question 76

76) You are on a steep downgrade and have reached your "safe" speed of 40 mph. You would apply the service brakes until your speed drops to____ mph.

Answer 76

35

Question 77

77) The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like:

Answer 77

Spring Pressure.

Question 78

78) Excessive heat in the brakes can cause the:

Answer 78

Brakes to fade or fail.

Question 79

79) To check the brake slack on S-cam brakes, you should park on:

Answer 79

Level ground, chock the wheels, and release the parking brakes.

Question 80

80) With air brake vehicles, the parking brakes should be used:

Answer 80

Whenever you leave the vehicle unattended.

Question 81

81) A truck with air brakes going 55 mph would require a stopping distance of:

Answer 81

More than 300 feet.