NC CDL Combination Vehicles Exam
QUESTIONS AND ANSWERS 100%
RATED CORRECT WITH 100% SURE
PASS|GRADED A+
You are coupling a semi-trailer to your tractor but have not yet backed under, the trailer is at the right
height when: - CORRECT ANSWERS It will be raised slightly when the tractor is backed under
it.
You should not back a tractor under a trailer until the whole air system is: - CORRECT ANSWERS
At normal pressure.
Which part of the kingpin should the locking jaws close around? - CORRECT ANSWERS The
shank.
When you get ready to back under the semi-trailer you should line up: - CORRECT ANSWERS
Directly in front of the trailer.
How should you test the tractor semi-trailer connection for security? - CORRECT ANSWERS
Pull gently forward in low gear against the locked trailer brakes, then look at it carefully.
When should you use the hand valve to park a combination vehicle? - CORRECT ANSWERS
Never.
You supply air to the trailer tanks by: - CORRECT ANSWERS Pushing in the trailer air supply
valve.
Why should you be sure that the fifth wheel plate is greased as required? - CORRECT ANSWERS
To prevent steering problems.
, 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: - CORRECT ANSWERS Applying and releasing the trailer brakes and
listening for brake sounds.
There are two things that a driver can do to prevent a rollover. They are: (1) Keep the cargo as close to
the ground as possible; and (2): - CORRECT ANSWERS Go slowly around turns.
Before you back under a trailer, make sure the: - CORRECT ANSWERS Trailer brakes are
locked.
If the service air line comes apart while you are driving a combination vehicle, but the emergency line
stays together, what will happen right away? - CORRECT ANSWERS Nothing is likely to
happen until you try to apply the brakes.
The air leakage rate for a combination vehicle (engine off, brakes on) should not be more than ___ PSI
per minute. - CORRECT ANSWERS 4
In normal driving, some drivers use the hand valve before applying the brake pedal to prevent a
jackknife. Which of these statements is true? - CORRECT ANSWERS If the trailer has not
spring brakes, you can drive away, but you will not have trailer brakes.
Why should you lock the tractor glad hands (or dummy couplers) to each other when you are not towing
a trailer? - CORRECT ANSWERS It will keep dirt and water out of the lines.
For coupling to be completed, the safety catch for the fifth wheel locking lever must be: - CORRECT
ANSWERS Over the locking lever.
The front trailer supports are up and trailer is resting on the tractor. Make sure: - CORRECT ANSWERS
There is enough clearance between the tractor frame and the landing gear.
QUESTIONS AND ANSWERS 100%
RATED CORRECT WITH 100% SURE
PASS|GRADED A+
You are coupling a semi-trailer to your tractor but have not yet backed under, the trailer is at the right
height when: - CORRECT ANSWERS It will be raised slightly when the tractor is backed under
it.
You should not back a tractor under a trailer until the whole air system is: - CORRECT ANSWERS
At normal pressure.
Which part of the kingpin should the locking jaws close around? - CORRECT ANSWERS The
shank.
When you get ready to back under the semi-trailer you should line up: - CORRECT ANSWERS
Directly in front of the trailer.
How should you test the tractor semi-trailer connection for security? - CORRECT ANSWERS
Pull gently forward in low gear against the locked trailer brakes, then look at it carefully.
When should you use the hand valve to park a combination vehicle? - CORRECT ANSWERS
Never.
You supply air to the trailer tanks by: - CORRECT ANSWERS Pushing in the trailer air supply
valve.
Why should you be sure that the fifth wheel plate is greased as required? - CORRECT ANSWERS
To prevent steering problems.
, 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: - CORRECT ANSWERS Applying and releasing the trailer brakes and
listening for brake sounds.
There are two things that a driver can do to prevent a rollover. They are: (1) Keep the cargo as close to
the ground as possible; and (2): - CORRECT ANSWERS Go slowly around turns.
Before you back under a trailer, make sure the: - CORRECT ANSWERS Trailer brakes are
locked.
If the service air line comes apart while you are driving a combination vehicle, but the emergency line
stays together, what will happen right away? - CORRECT ANSWERS Nothing is likely to
happen until you try to apply the brakes.
The air leakage rate for a combination vehicle (engine off, brakes on) should not be more than ___ PSI
per minute. - CORRECT ANSWERS 4
In normal driving, some drivers use the hand valve before applying the brake pedal to prevent a
jackknife. Which of these statements is true? - CORRECT ANSWERS If the trailer has not
spring brakes, you can drive away, but you will not have trailer brakes.
Why should you lock the tractor glad hands (or dummy couplers) to each other when you are not towing
a trailer? - CORRECT ANSWERS It will keep dirt and water out of the lines.
For coupling to be completed, the safety catch for the fifth wheel locking lever must be: - CORRECT
ANSWERS Over the locking lever.
The front trailer supports are up and trailer is resting on the tractor. Make sure: - CORRECT ANSWERS
There is enough clearance between the tractor frame and the landing gear.
