Combination Test - Texas CDL/ 44 Q&A/
Already Graded A+
In coupling, just before the tractor is coupled with the trailer you should: -
Answer: connect the emergency and service air lines.
In coupling, you should not move the tractor after it is coupled until you push in
the air supply knob and: - Answer: wait until the air pressure is normal.
What happens immediately if the service airline comes apart while driving, but
the emergency line is okay? - Answer: Nothing is likely to happen until you press
the brakes.
Page 1 of 7
, In coupling, before you back under the trailer, how do you lock the trailer brakes?
- Answer: Pull out the yellow air supply knob.
For the coupling to be complete, the safety catch for the fifth wheel locking lever
must be: - Answer: over the locking gear.
What is the air leakage rate for a combination vehicle with the engine and brakes
off? - Answer: Less than 3 PSI per minute.
What is the maximum air leakage rate for a combination vehicle with the engine
off and the brakes on? - Answer: 4 PSI per minute.
A driver crosses the air lines when hooking up to an old trailer. What will happen?
- Answer: If the trailer has no spring brakes, he or she could drive away but
wouldn't have trailer brakes.
To unlock the fifth wheel, pull the release handle to the: - Answer: open position.
When driving a set of doubles, it is necessary to close the: - Answer: back shut-off
valve in the last trailer.
You are coupling a semitrailer to your tractor but have not yet backed under. The
trailer is at the right height when: - Answer: it will be raised slightly when the
tractor is backed under it.
Page 2 of 7
Already Graded A+
In coupling, just before the tractor is coupled with the trailer you should: -
Answer: connect the emergency and service air lines.
In coupling, you should not move the tractor after it is coupled until you push in
the air supply knob and: - Answer: wait until the air pressure is normal.
What happens immediately if the service airline comes apart while driving, but
the emergency line is okay? - Answer: Nothing is likely to happen until you press
the brakes.
Page 1 of 7
, In coupling, before you back under the trailer, how do you lock the trailer brakes?
- Answer: Pull out the yellow air supply knob.
For the coupling to be complete, the safety catch for the fifth wheel locking lever
must be: - Answer: over the locking gear.
What is the air leakage rate for a combination vehicle with the engine and brakes
off? - Answer: Less than 3 PSI per minute.
What is the maximum air leakage rate for a combination vehicle with the engine
off and the brakes on? - Answer: 4 PSI per minute.
A driver crosses the air lines when hooking up to an old trailer. What will happen?
- Answer: If the trailer has no spring brakes, he or she could drive away but
wouldn't have trailer brakes.
To unlock the fifth wheel, pull the release handle to the: - Answer: open position.
When driving a set of doubles, it is necessary to close the: - Answer: back shut-off
valve in the last trailer.
You are coupling a semitrailer to your tractor but have not yet backed under. The
trailer is at the right height when: - Answer: it will be raised slightly when the
tractor is backed under it.
Page 2 of 7
