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CDL > 캄비네이션 vehicle > Flashcards

캄비네이션 vehicle Flashcards

1
Q

There are 2 things that a driver can do to prevent a rollover, they are: 1. Go slow around turns, and 2:
A. Keep both hands firmly on the steering.
B.Keep the cargo as close to the ground as possible
C. Keep the fifth wheel free play as small as possible

A

Keep the cargo as close to the ground as possible

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2
Q

You are coupling a tractor and a semitrailer and have connected the air lines, before backing under the trailer, you should:
A. Make sure that the trailer brakes are off
B. Supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes.
C. Pull ahead to test the glad hand connections.

A

Supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes.

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3
Q

After connecting the air lines, but before backing under the trailer, you should:
A. Make sure that the trailer brakes are off
B. Supply air to the trailer system and pull out the air supply knob.
C. Wall around the rig to be sure that it is clear.

A

Supply air to the trailer system and pull out the air supply knob.

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4
Q

The air leakage rate for a combination vehicle, engine off, brakes off, should be less than:
A. 1/2 psi per minute
B. 2 psi per minute
C. 3 psi per minute

A

3 psi per minute

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5
Q

When connecting the glad hands, press the 2 seals of the couplers together at a: What angle?

A

90 degree angle to one another

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6
Q

You’re driving combination vehicle when the trailer breaks away, pulling apart both air lines, you would expect the trailer brakes to come on and:
A. The trailer supply valve to stay open
B. The tractor to lose all air pressure
C. The tractor protection valve to close.

A

The tractor protection valve to close.

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7
Q

To unlock the fifth wheel, pull the release handle to the:
A. Open position
B. Neutral position
C. Closed position

A

Open position.

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8
Q

How should you test the tractor-semitrailer connection for security?
A. Put the tractor in gear and pull ahead with a sharp jerk
B. Rock the trailer back and forth with the trailer brakes locked.
C.Pull gently forward in low gear against the locked trailer brakes, then look at it carefully.

A

Pull gently forward in low gear against the locked trailer brakes, then look at it carefully.

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9
Q

In normal driving some drivers use the hand valve before the brake pedal to prevent a jackknife; which of these statements is true?
A. It is the best way to brake.
B. It should not be done.

A

It should not be done.

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10
Q

Offtracking or cheating, causes which of these to follow the widest path while making a turn?
A. Five axle tractor towing two 27 trailers
B. Five axle tractor towing 45 foot trailer

A

Five axle tractor towing 45 foot trailer.

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11
Q

When checking that the trailer is securely coupled to the tractor, the landing gear should be:
A. Fully raised
B. Slightly raised
C. Fully lowered

A

Slightly raised.

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12
Q

If the spring brakes don’t release when you push the trailer air supply control, you should:
A. Cross the air lines.
B. Check the electrical service cable
C. Check the air line connections

A

Check the air line connections

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13
Q

The best way to tell if your trailer has started to skid is to:
A. See it in your mirrors.
B. Hear the wheels skidding
C. Feel for pulling

A

See it in your mirrors.

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14
Q

The air leakage rate for a combination vehicle, engine off, brakes on, should be less than:

A

4 psi per minute

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15
Q

A tractor with a: shortest stopping distance?

A. Empty trailer
B. Fully loaded trailer
C. Lightly loaded trailer

A

Fully loaded trailer requires the shortest amount of stopping distance.

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16
Q

Air brake equipped trailers made before 1975:
A. Usually need a glad hand converter
B.Often do not have spring brakes

A

Often do not have spring brakes.

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17
Q

When checking the trailer’s emergency brakes, the tractor protection control valve should be placed in the:
A. Normal
B. Emergency position

A

Emergency position

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18
Q

A tractor-trailer vehicle combination, is most likely to roll over in a turn, when the configuration includes:
A. Double 45 foot trailer
B. Triple 27 foot trailer
C. Combo 45 and 27 foot.

A

Triple 27 foot trailers

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19
Q

To be safe, when driving behind other vehicle under good condition, you should have at least 1 second between your vehicle, and the vehicle ahead for each:
A. 10 feet of your vehicle’s length
B. 20 feet of your vehicle’s length
C. 30 feet of your vehicle’s length

A

10 feet of your vehicle’s length

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20
Q

After the trailer has been coupled to the tractor, the tractor protection control valve should be placed in the:
A. Down
B. Normal
C. Down

A

Normal position

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21
Q

Glad hands are used for connecting the:
A. Electric lines from the truck to the trailer.
B. Service and emergency air lines from the vehicle to the trailer

A

Service and emergency air lines from the vehicle to the trailer

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22
Q

What gear should the tractor transmission be in, after you have uncoupled the trailer and are inspecting the trailer supports?

A. Low reverse
B. Neutral

A

Neutral

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23
Q

If you cannnot make a turn without entering another traffic lane, you should:

A. Turn wide before you start your turn
B. Turn wide as you complete your turn.

A

Turn wide as you complete your turn.

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24
Q

Where should the tractor be when you inspect the landing gear after uncoupling a trailer?

A. With the fifth wheel directly beneath the king pin.
B. With the tractor frame under the trailer

A

With the tractor frame under the trailer

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25
Q

The fifth wheel locking lever is not locked after the jaws close around the king pin, this means that:

A. The coupling is not right and should be fixed before driving the coupled unit
B. The parking lock is off and you may drive away

A

The coupling is not right and should be fixed before driving the coupled unit

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26
Q

To stop a trailer skid, you should:

A. Countersteer
B. Release the service brakes

A

Release the service brakes

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27
Q

When coupling, the proper position of the fifth wheel is:

A. Level with the ground
B. Titled down towards the end of the tractor

A

Tilted down towards the end of the tractor

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28
Q

Semitrailers made before 1975, that are equipped with air brakes:

A. Have only a service air line
B. Often do no have spring brakes

A

Often do no have spring brakes

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29
Q

Why should you be sure that the fifth wheel plate is greased as required?

A. to ensure good electrical connections.
B. To prevent steering problems

A

To prevent steering problems

30
Q

Air and electric lines from the tractor to the trailer should be:

A. Resting on the frame of the tractor
B. Secured, but with enough slack for turns

A

Secured, but with enough slack for turns

31
Q

Loss of air pressure in the emergency line causes?

A. An increase in air pressure to the service line
B. The relay valves to close.
C. The trailer’s emergency brakes to come on.

A

The trailer’s emergency brakes to come on.

32
Q

Compared to a straight truck or bus, there are:

A. more things to inspect
B. fewer things to inspect

A

More things to inspect on a combination vehicle.

33
Q

Before you back under a trailer, make sure the:

A. Air brakes are off
B. Trailer brakes are locked.

A

Trailer brakes are locked.

34
Q

In general, the higher the center of gravity of you truck, the:

A. more stable
b. easier to turn over

A

easier it is to turn over.

35
Q

When should you use the hand valve to park a combination vehicle?

A. to park on a grade
B. Never

A

Never

36
Q

The trailer hand valve (also called the trolley valve or Johnson bar) works the trailer brakes. The trailer hand valve is used only to test the trailer brakes.

A

hand valve= only to test the trailer brakes

37
Q

The safety catch for the fifth wheel locking lever must be:

A. Straight up for a coupling to be complete
B. over the locking lever for a coupling to be complete.
C. Through the locking lever for a coupling to be complete.

A

over the locking lever for a coupling to be complete.

38
Q

The trailer air supply control, also called the tractor protection valve control, should automatically close when the air pressure falls to between:

A. 100 to 125 psi
B. 20 to 45 psi

A

20 to 45 psi

39
Q

Air lines on a combination vehicle are often colored to keep from getting them mixed up, the emergency line is: What color

A. Black
B. Red
C. Blue

A

Red, the service line is blue.

40
Q

When backing a tractor under a trailer, you should:

A. Always approach the trailer at a slight angle
B. Always use the lowest reverse gear.

A

Always use the lowest reverse gear.

41
Q

You have a major leak in the service line and you put on the brakes; service air pressure will escape and cause the:

A. Trailer tank pressure to be lost
B. Trailer emergency brakes to come on.

A

Trailer emergency brakes to come on.

42
Q

You have coupled with a semitrailer, where should you put the front trailer supports before driving away?

A. Fully raised
B. Raised 3/4 way

A

Fully raised with the crank handle secured in its bracket.

43
Q

You have pushed in the trailer supply valve, you should not move the tractor until the whole air system is:

A. Between 60 to 80 psi
B. At normal pressure.

A

At normal pressure.

44
Q

The front trailer supports are up and the trailer is resting on the tractor, make sure:

A. There is enough clearance between the tractor frame and the landing gear.
B. There is enough clearance between the upper and lower fifth wheel

A

There is enough clearance between the tractor frame and the landing gear.

45
Q

When driving a set of doubles, it is necessary to close the:

A. Back shut-off valve in the last trailer.
B. Front shut-off valve in the last trailer.

A

Back shut-off valve in the last trailer.

46
Q

You are coupling a tractor to a semitrailer and have backed up but are not under it, what should you hook up before backing under?

A. The emergency and service air lines.
B. Electrical service cable

A

The emergency and service air lines.

47
Q

When uncoupling a trailer, after you have shut off the trailer air supply and locked the trailer brakes, you should:

A. Back up gently to ease pressure on the fifth wheel locking jaws.
B. Begin to lower the trailer landing gear.

A

Back up gently to ease pressure on the fifth wheel locking jaws.

48
Q

Which of these statements is true?

A. Bobtail tractor can take longer to stop than a combination vehicle loaded to maximum gross weight.
B. Light vehicle need more braking power to stop than heavy ones

A

Bobtail tractor can take longer to stop than a combination vehicle loaded to maximum gross weight.

49
Q

Which one takes longer to stop? Bobtail or combination vehicle loaded to maximum gross.

A

Bobtail.

50
Q

After you have coupled the trailer, you should begin raising the landing gear by using the :

A. High gear
B. Low gear

A

Low gear.

51
Q

After you supply air to the trailer, make sure the air lines are not crossed and the trailer brakes are working, this is done by:

A. Applying and releasing the trailer brakes and listening for brake sounds.
B. Turning on the parking brakes from the cab.

A

Applying and releasing the trailer brakes and listening for brake sounds.

52
Q

The tractor protection valve on a towing vehicle ensures that an air-loss problem in the trailer does not result in loss of air from the towing vehicle.

A

Purpose of the tractor protection valve

53
Q

The tractor protection valve will close and the trailer emergency brakes will come on when there is a major leak in the:

A. Service brake line
B. Emergency brake line

A

Emergency brake line.

54
Q

What would happen if the air lines are crossed when you hook up to an old trailer?

A. The hand valve will apply the tractor brakes instead of the trailer brakes
B. If the trailer has no spring brakes, you could drive away but you would not have trailer brakes.

A

If the trailer has no spring brakes, you could drive away but you would not have trailer brakes.

55
Q

Spring brakes are not air applied like service brakes. They apply when air pressure leaves the brake chamber and release when air pressure builds up in the chamber.

A

Spring brakes vs air brakes

56
Q

If the service air line comes apart while you are driving a combination vehicle, but the emergency line stays together; what would happen right away?

A. The emergency trailer brakes will come on.
B. Nothing is likely to happen until you try to apply the brakes.

A

Nothing is likely to happen until you try to apply the brakes.

57
Q

Which part of the king pin should the locking jaws close around?

A. the base
B. the shank

A

The shank

58
Q

Why should you lock the tractor glad hands to each other - or dummy couplers - when you are not towing a trailer?

A. It will keep dirt and water out of the lines.
B. If you didn’t, you could never build system pressure.

A

It will keep dirt and water out of the lines.

59
Q

When you get ready to back under a semi-trailer, you should line up:

A. Directly in front of the trailer.
B. The left rear outer dual wheel with the king pin.

A

Directly in front of the trailer.

60
Q

A driver crosses the air lines when hooking up to an old trailer, what will happen?

A. The brake pedal will work the trailer spring brakes instead of the air brakes
B. If the trailer has no spring brakes, he or she could drive away but wouldn’t have trailer brakes.

A

If the trailer has no spring brakes, he or she could drive away but wouldn’t have trailer brakes.

61
Q

You supply air to the trailer tank by:

A. Pulling out the trailer air supply valve.
B. Pushing in the trailer air supply valve.

A

Pushing in the trailer air supply valve.

62
Q

You should not back a tractor under a trailer until the whole air system is:

A. Normal pressure
B. 60-80 psi

A

At normal pressure.

63
Q

After you locked the kingpin into the fifth wheel, you should check the connection by:

A. Pulling the tractor ahead sharply.
B. Pulling the tractor ahead gently.

A

Pulling the tractor ahead gently with the trailer brakes locked.

64
Q

How much space should be between the upper and lower fifth wheel after coupling?

A. None
B. Just enough to see light through it

A

None

65
Q

You are coupling a semitrailer to your tractor, but have not yet backed under, the trailer is at the right height when:

A. It will be raised slightly when the tractor is backed under it.
B. The end of the king pin is even with the top of the fifth wheel.

A

It will be raised slightly when the tractor is backed under it.

66
Q

When do you need to use chocks to park a trailer that doesn’t have spring brakes?

A. only on an incline
B. always

A

Always

67
Q

The hand valve should be used:

A. As a parking brake.
B. To test the trailer brakes

A

To test the trailer brakes

68
Q

When you are uncoupling a loaded trailer, you should lower the landing gear until it:

A. Just reaches the ground
B. makes firm contact with the ground, then crank it in low gear a few extra turns.

A

makes firm contact with the ground, then crank it in low gear a few extra turns.

69
Q

A trailer is most likely to jackknife when it is:

A. overloaded
B. empty

A

Empty

70
Q

Your emergency air line breaks or gets pulled apart while you are driving, the loss of pressure will cause the:

A. Trailer supply valve to open
B. Air compressor to unload instead of pumping air.
C. emergency trailer brakes to come on.

A

emergency trailer brakes to come on.

CDL (6 decks)

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