Texas CDL Combination Test Exam
Questions and Answers
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.
, Texas CDL Combination Test Exam
Questions and Answers
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: -
Questions and Answers
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.
, Texas CDL Combination Test Exam
Questions and Answers
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: -
