CDL QUIZ Air Brakes Flashcards Preview

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Flashcards in CDL QUIZ Air Brakes Deck (47):
1

2. Do converter dollies have spring brakes?

Yes

2

4. What is the emergency air-line for?

1 supplies air to the trailer air tanks; 2 controls the emergency brakes on combination vehicles.

3

What are the maximum leakage rates?

 The loss rate should be less than two psi in one minute for single vehicles and less than three psi in one minute for combination vehicles

4

1. What might happen if the trailer is too high when you try to couple?

if the trailer is too high, it may not couple correctly

5

6. Where are shut-off valves?

at the back of trailers used to tow other trailers

6

6. Why should you pull a dolly out from under a trailer before you disconnect it from the trailer in front?

the dolly tow bar may fly up and possibly cause injury and making it quite difficult to recouple

7

Why must air tanks be drained?

Compressed air usually has some water and some compressor oil in it, which is bad for the air brake system

8

1. Why should you not use the trailer hand valve while driving?

danger of making the trailer skid.

9

What are spring brakes?

 held on by mechanical force

10

How can you test the low pressure warning signal?

Shut the engine off when you have enough air pressure Turn the electrical power on and step on and off the brake pedal; warning signal must come on before the pressure drops to less than 60 psi (or tank with the lowest air pressure, in dual air systems)

11

How often should you drain air tanks?

at the end of each day of driving

12

5. What do you check when making a visual check of coupling?

Make sure there is no space between upper and lower 5th wheel and that the locking jaws are locked on the kingpin

13

How do you know if your vehicle is equipped with antilock brakes?

 Tractors, trucks, and buses will have yellow ABS malfunction lamps on the instrument panel

14

How can you check that the spring brakes come on automatically?

 stepping on and off the brake pedal to reduce tank pressure. The tractor protection valve and parking brake valve should pop out on a tractor-trailer combination vehicle  when the air pressure falls to the manufacturer’s specification (20 – 45 psi). This will cause the spring brakes to come on.

15

1. What is a converter dolly?

a coupling device of one or two axles and a fifth wheel

16

2. Describe what the trailer air supply control does.

keeps air in the tractor or truck brake system should the trailer break away or develop a bad leak.

17

How can you check slack adjusters?

Chock the vehicle and release the park brake

18

6. What type of trailers can get stuck on the railroad-highway crossings?

Low slung units (lowboy, car carrier, moving van, possum-belly livestock trailer); Single-axle tractor pulling a long trailer

19

8. Should the shut-off valves on the rear of the last trailer be open or closed? On the first trailer in a set of doubles? On the middle trailer of a set of triples?

• Rear of front trailers: OPEN; Rear of last trailer: CLOSED; Converter dolly air tank drain valve: CLOSED

20

3. Describe what the service line is for.

trailer brakes

21

4. How do you check to make sure trailer height is correct before coupling?

It must be slightly lower than the center of the fifth wheel so trailer is raised slightly when dolly is pushed under

22

4. What is off-tracking?

When a vehicle goes around a corner, the rear wheels follow a different path than the front wheels.

23

3. What three methods can you use to secure a second trailer before coupling?

Drive tractor close to the trailer and connect the emergency line charge the trailer air tank and disconnect the emergency line. This will set the emergency brakes

24

2. After coupling, how much space should be between the upper and lower fifth wheel?

no space

25

How should you brake when you drive a tractor-trailer combination with ABS?

Normally

26

5. How do you know if your trailer is equipped with antilock brakes?

Warning Indicators on the control panel or label on the side of the trailer

27

Front wheel brakes are good under all conditions. True or False?

TRUE

28

3. Why should you not use the trailer hand brake to straighten out a jackknifing trailer?

the brakes on the trailer wheels cause the skid

29

4. To drive you need to raise the landing gear only until it just lifts off the pavement. True or False?

FALSE

30

7. What should you check for when inspecting the converter dolly? The pintle hook?

Position combination as close as possible to; converter dolly; Move dolly to rear of first semitrailer and couple; it to the trailer; Lock pintle hook; Secure dolly support in raised position; Pull dolly into position as close as possible to; nose of the second semitrailer; Lower dolly support; Unhook dolly from first trailer; Wheel dolly into position in front of second trailer; in line with the kingpin

31

1. Which shut-off valves should be open and which closed?

Rear of front trailers: OPEN; Rear of last trailer: CLOSED.

32

3. How can you test the tractor protection valve?

At normal pressure, shut the engine off; Step on and off the brake several times to reduce the air pressure; the tractor protection valve control should pop out

33

What is a supply pressure gauge used for?

These gauges tell you how much pressure is in the air tanks.

34

5. When you back a trailer, you should position your vehicle so you can back in a curved path to the driver’s side. True or False?

TRUE

35

10. How do you know if your converter dolly is equipped with antilock brakes?

Dollies manufactured on or after March 1, 1998, are required to have a lamp on the left side.

36

What factors can cause brakes to fade or fail?

excessive heat caused by using them too much and not relying on the engine braking effect

37

5. Why should you use chocks when parking a trailer without spring brakes?

the air will leak away and then there will be no brakes

38

Why should you be in the proper gear before starting down a hill?

To use the engine power as the primary braking source

39

The use of brakes on a long, steep downgrade is only a supplement to the braking effect of the engine. True or False?

TRUE

40

2. When you turn suddenly while pulling doubles, which trailer is most likely to turn over?

the rear trailer is twice as likely to turn over as the tractor.

41

2. How can you test that air flows to all trailers?

Use the tractor parking brake or chock the wheels; Wait for normal air pressure, then push in the red "trailer air supply" knob to supply air to the emergency (supply) lines; Use the trailer handbrake to provide air to the service line; at the rear, open the emergency line shutoff valve; You should hear air

42

3. You should look into the back of the fifth wheel to see if it is locked onto the kingpin. True or False?

TRUE

43

1. What two things are important to prevent rollover?

keep the cargo as close to the ground as possible, and drive slowly around turns

44

All vehicles with air brakes must have a low air pressure warning signal. True or False?

TRUE

45

9. How can you test that air flows to all trailers?

Go to the rear of the rig. Open the emergency line shut-off valve at the rear of the last trailer. You should hear air escaping, showing the entire system is charged.

46

If you are away from your vehicle only a short time, you do not need to use the parking brake. True or False?

FALSE

47

What is a dual air brake system?

 A dual air brake system has two separate air brake systems, which use a single set of brake controls