Combination Test - Texas CDL questions
and answers 2024\2025 A+ Grade
In coupling, just before the tractor is coupled with the trailer you should:
- correct 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:
- correct answer wait until the air pressure is normal.
What happens immediately if the service air line comes apart while driving, but the emergency line is
okay?
- correct answer Nothing is likely to happen until you press the brakes.
In coupling, before you back under the trailer, how do you lock the trailer brakes?
- correct 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:
- correct answer over the locking gear.
What is the air leakage rate for a combination vehicle with the engine and brakes off?
- correct 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?
- correct answer 4 PSI per minute.
A driver crosses the air lines when hooking up to an old trailer. What will happen?
- correct 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:
- correct answer open position.
When driving a set of doubles, it is necessary to close the:
- correct 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:
- correct answer it will be raised slightly when the tractor is backed under it.
Air and electric lines from the tractor to the trailer should be:
- correct answer secured, but with enough slack for turns.
When uncoupling a trailer, after you have shut off the trailer air supply and locked the trailer brakes, you
should:
- correct answer back up gently to ease pressure on the fifth wheel locking jaws.
Glad hands are used for connecting the:
- correct answer service and emergency air lines from the vehicle to the trailer.
You should not back a tractor under a trailer until the whole air system is:
- correct answer at normal pressure.
If the spring brakes don't release when you push the trailer air supply control, you should:
- correct answer check the air line connections.
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?
- correct answer The emergency and service air lines.
In general, the higher the "center of gravity" of your truck the:
- correct answer easier it is to turn over.
and answers 2024\2025 A+ Grade
In coupling, just before the tractor is coupled with the trailer you should:
- correct 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:
- correct answer wait until the air pressure is normal.
What happens immediately if the service air line comes apart while driving, but the emergency line is
okay?
- correct answer Nothing is likely to happen until you press the brakes.
In coupling, before you back under the trailer, how do you lock the trailer brakes?
- correct 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:
- correct answer over the locking gear.
What is the air leakage rate for a combination vehicle with the engine and brakes off?
- correct 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?
- correct answer 4 PSI per minute.
A driver crosses the air lines when hooking up to an old trailer. What will happen?
- correct 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:
- correct answer open position.
When driving a set of doubles, it is necessary to close the:
- correct 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:
- correct answer it will be raised slightly when the tractor is backed under it.
Air and electric lines from the tractor to the trailer should be:
- correct answer secured, but with enough slack for turns.
When uncoupling a trailer, after you have shut off the trailer air supply and locked the trailer brakes, you
should:
- correct answer back up gently to ease pressure on the fifth wheel locking jaws.
Glad hands are used for connecting the:
- correct answer service and emergency air lines from the vehicle to the trailer.
You should not back a tractor under a trailer until the whole air system is:
- correct answer at normal pressure.
If the spring brakes don't release when you push the trailer air supply control, you should:
- correct answer check the air line connections.
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?
- correct answer The emergency and service air lines.
In general, the higher the "center of gravity" of your truck the:
- correct answer easier it is to turn over.
