COMBINATION VEHICLE FINAL EXAM
You are hooking a tractor to a semi trailer and have backed up but are not under it.What
should you do before backing under the trailer? - Answers- B. Hook up the emergency
and service air lines
After pushing in the trailer supply valve, you should not move the tractor until the whole
air system is: - Answers- B. At normal pressure
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: - Answers- C. Reduce speed before
entering turns
With the engine off and the brakes released, a combination vehicle air brake system
should not leak more than ____________ psi in one minute - Answers- C. 3
the hand valve should be used to park a combination vehicle when? - Answers- D.
Never
Air lines on a combination vehicle are often colored to keep from getting them mixed up.
The emergency line is: - Answers- A. Red
How do you supply air to the tank on the trailer? You supply air to the trailer tank by: -
Answers- A. Pushing in the trailer air supply valve
In normal driving, some drivers use the trolley (hand) valve before the brake pedal in
order to prevent trailer skids. Which of these statements is true? - Answers- A. It should
never be done
You are hooking up a tractor and semi trailer. You have connected both airlines. before
backing up under the trailer, you should: - Answers- B Supply air to the trailer system,
then pull out the air supply knob to lock the trailer
When backing up under a trailer, you should line up: - Answers- C. Directly in front of
the trailer
If the service line disconnects while you are driving, what will happen right away? -
Answers- D. Nothing is likely to happen until you try the brakes
After hooking up, you should check the fifth wheel connection by: - Answers- D. Pulling
the tractor ahead gently with the trailer brakes locked
, The fifth wheel locking lever is not locked after the jaws close around the kingpin. This
means, that: - Answers- D. Coupling is not corrected and should be corrected before
driving the coupled unit
A driver crosses the airlines when hooking up to an old trailer. What will happen? -
Answers- C. If the trailer has no spring brakes, you could drive away buy you would not
have trailer brakes
After coupling a semi trailer, you should crank up the front trailer supports(dollies) how?
- Answers- C. Fully raised with the crank handle secured in its bracket
Air brakes equipped trailer made before 1972: - Answers- A. Usually do not have spring
brakes
When hooking a tractor to a trailer, you will know the trailer is at the right height when
the: - Answers- D. The coupling surface of the trailer is just below the middle of the
tractor fifth wheel
You are driving a combination vehicle when the trailer brakes away and pulls apart the
airlines. You would expect the trailer brakes to apply and: - Answers- B. the tractor
brakes to keep working properly
How much space should be between the upper and lower fifth wheel plates? -
Answers- D. None
When pulling a trailer, why is it good idea to lock the glad hands together or to a dummy
coupler - Answers- C.It keeps the dirt and water out the lines
Off tracking can be best described as: - Answers- D. thee rear wheels of the trailer will
track further to the inside of a turn than the wheels of the tractor
When should you use the hand valve to park a combination vehicle? - Answers- D.
Never
You have coupled with a semi trailer. Where should you put the front trailer supports
before driving away? - Answers- C. Fully raised with the crank handle secured in the
bracket
You supply air to the trailer tanks by: - Answers- A. Pushing in the trailer air supply
valve
You are coupling a tractor to a semi trailer and have backed up but are not under it.
What should you hook up before backing under? - Answers- B. The emergency and
service air lines
You are hooking a tractor to a semi trailer and have backed up but are not under it.What
should you do before backing under the trailer? - Answers- B. Hook up the emergency
and service air lines
After pushing in the trailer supply valve, you should not move the tractor until the whole
air system is: - Answers- B. At normal pressure
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: - Answers- C. Reduce speed before
entering turns
With the engine off and the brakes released, a combination vehicle air brake system
should not leak more than ____________ psi in one minute - Answers- C. 3
the hand valve should be used to park a combination vehicle when? - Answers- D.
Never
Air lines on a combination vehicle are often colored to keep from getting them mixed up.
The emergency line is: - Answers- A. Red
How do you supply air to the tank on the trailer? You supply air to the trailer tank by: -
Answers- A. Pushing in the trailer air supply valve
In normal driving, some drivers use the trolley (hand) valve before the brake pedal in
order to prevent trailer skids. Which of these statements is true? - Answers- A. It should
never be done
You are hooking up a tractor and semi trailer. You have connected both airlines. before
backing up under the trailer, you should: - Answers- B Supply air to the trailer system,
then pull out the air supply knob to lock the trailer
When backing up under a trailer, you should line up: - Answers- C. Directly in front of
the trailer
If the service line disconnects while you are driving, what will happen right away? -
Answers- D. Nothing is likely to happen until you try the brakes
After hooking up, you should check the fifth wheel connection by: - Answers- D. Pulling
the tractor ahead gently with the trailer brakes locked
, The fifth wheel locking lever is not locked after the jaws close around the kingpin. This
means, that: - Answers- D. Coupling is not corrected and should be corrected before
driving the coupled unit
A driver crosses the airlines when hooking up to an old trailer. What will happen? -
Answers- C. If the trailer has no spring brakes, you could drive away buy you would not
have trailer brakes
After coupling a semi trailer, you should crank up the front trailer supports(dollies) how?
- Answers- C. Fully raised with the crank handle secured in its bracket
Air brakes equipped trailer made before 1972: - Answers- A. Usually do not have spring
brakes
When hooking a tractor to a trailer, you will know the trailer is at the right height when
the: - Answers- D. The coupling surface of the trailer is just below the middle of the
tractor fifth wheel
You are driving a combination vehicle when the trailer brakes away and pulls apart the
airlines. You would expect the trailer brakes to apply and: - Answers- B. the tractor
brakes to keep working properly
How much space should be between the upper and lower fifth wheel plates? -
Answers- D. None
When pulling a trailer, why is it good idea to lock the glad hands together or to a dummy
coupler - Answers- C.It keeps the dirt and water out the lines
Off tracking can be best described as: - Answers- D. thee rear wheels of the trailer will
track further to the inside of a turn than the wheels of the tractor
When should you use the hand valve to park a combination vehicle? - Answers- D.
Never
You have coupled with a semi trailer. Where should you put the front trailer supports
before driving away? - Answers- C. Fully raised with the crank handle secured in the
bracket
You supply air to the trailer tanks by: - Answers- A. Pushing in the trailer air supply
valve
You are coupling a tractor to a semi trailer and have backed up but are not under it.
What should you hook up before backing under? - Answers- B. The emergency and
service air lines
