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CDL > COMBINATION VEHICLES > Flashcards

COMBINATION VEHICLES Flashcards

1
Q

You supply air in the tanks by

A

pushing in the trailer air supply valve

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2
Q

Loss of air pressure in the emergency line causes

A

the trailer’s emergency brakes to come on

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3
Q

A tractor with a _ trailer requires the shortest amount of stopping distance

A

fully loaded

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4
Q

Which of these statements is true?

A

bobtails tractors can take longer to stop than fully loaded combination vehicles

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5
Q

If you cannot make a right turn without swinging into another lane, you should:

A

turn wide as you complete the turn

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6
Q

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

A

emergency

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7
Q

Off tracking or “cheating” causes which of these to follow the widest path while making a turn?

A

3 axle tractor towing a 45 ft trailer

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8
Q

If your vehicle gets stuck on a railroad crossing, you should:

A

get out of the vehicle and away from the tracks

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9
Q

When driving a set of double trailers, it is necessary to close shut-off valves
on some trailers. Where are these valves located?

A

at the back of trailers used to tow other trailers

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10
Q

Before you back under a trailer, make sure of what?

A

the trailer brakes are locked

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11
Q

To unlock the fifth wheel, you pull the handle to what position?

A

open

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12
Q

After connecting the air lines but before backing under the trailer, you
should:

A

supply air to the trailer, then pull out the trailer air supply valve

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13
Q

You are coupling a tractor to a semi-trailer and you have backed up but are not yet under it. What should you hook up before backing under it?

A

the emergency and service air lines

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14
Q

You are coupling a tractor to a trailer. The trailer is at the right height when:

A

the trailer is raised slightly when the tractor is backed under it

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15
Q

Why should you connect the air lines to a dummy coupler when they are not in use?

A

it will keep dirt and water out of the lines

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16
Q

The air leakage rate for a combination vehicle with the ENGINE OFF and the
BRAKES OFF should be less than _ per minute.

A

3 psi

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17
Q

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

A

secured properly with enough slack for turns

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18
Q

Air brake equipped trailers made before 1975

A

often do not have spring brakes

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19
Q

The hand valve should be used

A

to test the trailer brakes

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20
Q

The air leakage rate for a combination vehicle with the ENGINE OFF and the
BRAKES ON should be less than__ per minute.

A

4 psi

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21
Q

Your emergency line breaks or gets pulled apart while driving. The loss of
pressure will cause the:

A

emergency trailer brakes to come on

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22
Q

You have pushed in the trailer air supply valve. You should not move the
vehicle until the whole system is:

A

at normal pressure

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23
Q

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

A

never

24
Q

The best way to tell that your trailer has started to skid is to:

A

see it in your mirrors

25
Q

A trailer is most likely to jackknife when it is:

A

empty

26
Q

If the service line comes apart but the emergency line stays together, what
will happen right away?

A

nothing is likely to happen until you try to apply the brakes

27
Q

When backing a tractor under a trailer you should:

A

always use lowest reverse gear

28
Q

After you have coupled the trailer, you should begin raising the landing gear
using what gear?

A

low gear

29
Q

You will know the trailer you are using has ABS by:

A

a yellow malfunction lamp on the left side

30
Q

If you cross the air lines while coupling to an old trailer what will happen?

A

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

31
Q

When should you get out of your vehicle when you are backing a trailer?

A

when you are unsure of your path of travel

32
Q

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

A

makes firm contact with the ground, then turn it a few extra cranks in
low gear

33
Q

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

A

none

34
Q

The front trailer supports are up and the trailer is resting on the tractor.
Make sure:

A

there is enough clearance between the frame and the landing gear

35
Q

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

A

to prevent steering problems

36
Q

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

A

pulling the tractor ahead gently with trailer brakes locked

37
Q

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

A

applying and releasing the trailer brakes and listening for sounds

38
Q

you should maintain at least one second of distance for each _ of vehicle length as following distance.

A

10 ft

39
Q

Two things you can do to prevent rolling over are keep the cargo as low to the ground as possible, and:

A

go slow around turns

40
Q

You have a major leak in the service line and you put on the brakes. Service air pressure will escape and if it goes low enough will cause the:

A

trailer emergency brakes to come on

41
Q

When uncoupling a trailer, after you have locked the trailer brakes, you
should:

A

back up gently to ease pressure on the fifth wheel jaws

42
Q

When do you need to use chocks to park a trailer that does not have spring brakes?

A

always

43
Q

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

A

the coupling is not right and should be fixed before driving

44
Q

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

A

directly in front of the trailer

45
Q

After you have coupled to a trailer, the tractor protection valve should be placed in the _ position.

A

normal

46
Q

How should you test the trailer connection for security?

A

pull gently forward with the trailer brakes locked, then look at it carefully

47
Q

The trailer air supply valve should automatically close when air pressure
falls to what range?

A

20-45 psi

48
Q

What part of the kingpin should the jaws be locked around?

A

the shank

49
Q

The higher your center of gravity of your truck, the:

A

easier it is to turn over

50
Q

When checking that the trailer is securely coupled to the tractor, the landing gear should be:

A

slightly raised

51
Q

If you must back your trailer on a curved path, you should position your
vehicle so you can back

A

to the drivers side

52
Q

If your ABS is not working on your trailer, you should

A

drive normally but get the system serviced soon

53
Q

Compared to a straight truck or bus, there are _ things to inspect on a combination vehicle.

A

more

54
Q

Air lines are often colored. The emergency line is? The service line is?

A

red(emergency) blue(service)

55
Q

To stop a trailer skid you should

A

release service brake

56
Q

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

A

neutral

57
Q

You have coupled to a trailer. Where should the landing gear be before
driving away?

A

fully raised with the crank handle secure in the bracket

CDL (3 decks)

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