© EVERLY 2025 ALL RIGHTS RESERVED.
CDL - Air Brakes Exam Questions And
Answers 100% Pass.
After every working day - Answer✔Oil and water usually collect in compresed air tanks. If you
do not have an automatic tank drain, when should you drain the air tanks?
Why drain water from the compressed air tanks? - Answer✔Water can freeze in cold weather
and cause brake failure.
The air brake system for a straight truck or bus should not leak at a rate of more than
__________ psi per minute with the engine off and the brakes released. - Answer✔2
To make an emergency stop with air brakes, using the stab braking method, you should: -
Answer✔Press on the brake pedal as hard as you can, release the brakes when the wheels locked,
put on the brakes again when the wheels start rolling.
You should know that your brakes are fading when: - Answer✔You have to apply the brake
pedal harder to control speed on a downgrade.
If the air compressor should develop a leak, what keeps the air in the tanks? - Answer✔The one
way check valve.
To check the brake slack on S-cam brakes you should park on: - Answer✔Park on level ground,
chock the wheels, and release the parking brakes.
The application pressure gauge shows how much pressure you have: - Answer✔When you are
applying to the brakes.
The spring brakes used on the chambers in a straight truck will bring you to a stop when air
pressure drops below ______ psi. - Answer✔20
The safety valve is set to automatically reduce pressure at ________ psi. - Answer✔150
Your truck has a dual air system and one system loses its pressure. What will happen? -
Answer✔Either the front or back brake will not be fully operational.
If your truck or bus has dual parking control valves, you can use pressure from a separate tank
to: - Answer✔Release the spring emergency/parking brakes to move a short distance.
If your truck has a properly functioning dual air brake system and minimum size air tanks. The
air pressure should build from 85 to 100 psi within _______ seconds? - Answer✔45
, © EVERLY 2025 ALL RIGHTS RESERVED.
During normal driving, spring brakes are usually held back by: - Answer✔Air pressure
The air compressor stops pumping air at what psi? - Answer✔125
The driver must be able to see a warning before pressure in the service air tanks falls below
________ psi. - Answer✔55
Excessive use of the service brakes results in overheating which can lead to: -
Answer✔Expansion of the brake drums.
The most common type of foundation brake found on heavy vehicles is the: - Answer✔S-cam
drum
If you must make an emergency stop, brake so you: - Answer✔Can steer and your vehicle stays
in a straight line.
The braking power of the spring brakes: - Answer✔Depends on the service brakes being in
adjustment.
The air brake lag distance at 55 mph on dry pavement adds about _______ feet. - Answer✔32
Total stopping distance for air brakes is longer than that for hydraulic brakes due to _______
distance. - Answer✔Brake lag
It is accepted that too much heat caused by using your brakes too often can also cause: -
Answer✔Brake fade or failure
Repeatedly pressing and releasing (fanning) the brake pedal may result in: - Answer✔The loss of
brake air pressure
The brake system that applies and releases the brakes when the driver uses the brake pedal is the
________ brake system. - Answer✔Service
A slack adjuster's free play needs to be adjusted if it is more than about how many inches when
you pull hard on it? - Answer✔1 inch
The brake pedal in an air brake system: - Answer✔Controls the air pressure applied to put in the
brakes.
Under normal conditions in order to engage the parking brakes the driver must first: -
Answer✔Let the air out of the spring brakes.
Which of these is NOT a proper time to apply the parking brakes? - Answer✔If your brakes are
very hot.
What is the first thing you should do when a low air pressure warning comes on: - Answer✔Stop
and safety park as soon as possible.
The parking or emergency brake on a heavy vehicle can only be held in position by something
that cannot peak away, like: - Answer✔Spring Pressure
CDL - Air Brakes Exam Questions And
Answers 100% Pass.
After every working day - Answer✔Oil and water usually collect in compresed air tanks. If you
do not have an automatic tank drain, when should you drain the air tanks?
Why drain water from the compressed air tanks? - Answer✔Water can freeze in cold weather
and cause brake failure.
The air brake system for a straight truck or bus should not leak at a rate of more than
__________ psi per minute with the engine off and the brakes released. - Answer✔2
To make an emergency stop with air brakes, using the stab braking method, you should: -
Answer✔Press on the brake pedal as hard as you can, release the brakes when the wheels locked,
put on the brakes again when the wheels start rolling.
You should know that your brakes are fading when: - Answer✔You have to apply the brake
pedal harder to control speed on a downgrade.
If the air compressor should develop a leak, what keeps the air in the tanks? - Answer✔The one
way check valve.
To check the brake slack on S-cam brakes you should park on: - Answer✔Park on level ground,
chock the wheels, and release the parking brakes.
The application pressure gauge shows how much pressure you have: - Answer✔When you are
applying to the brakes.
The spring brakes used on the chambers in a straight truck will bring you to a stop when air
pressure drops below ______ psi. - Answer✔20
The safety valve is set to automatically reduce pressure at ________ psi. - Answer✔150
Your truck has a dual air system and one system loses its pressure. What will happen? -
Answer✔Either the front or back brake will not be fully operational.
If your truck or bus has dual parking control valves, you can use pressure from a separate tank
to: - Answer✔Release the spring emergency/parking brakes to move a short distance.
If your truck has a properly functioning dual air brake system and minimum size air tanks. The
air pressure should build from 85 to 100 psi within _______ seconds? - Answer✔45
, © EVERLY 2025 ALL RIGHTS RESERVED.
During normal driving, spring brakes are usually held back by: - Answer✔Air pressure
The air compressor stops pumping air at what psi? - Answer✔125
The driver must be able to see a warning before pressure in the service air tanks falls below
________ psi. - Answer✔55
Excessive use of the service brakes results in overheating which can lead to: -
Answer✔Expansion of the brake drums.
The most common type of foundation brake found on heavy vehicles is the: - Answer✔S-cam
drum
If you must make an emergency stop, brake so you: - Answer✔Can steer and your vehicle stays
in a straight line.
The braking power of the spring brakes: - Answer✔Depends on the service brakes being in
adjustment.
The air brake lag distance at 55 mph on dry pavement adds about _______ feet. - Answer✔32
Total stopping distance for air brakes is longer than that for hydraulic brakes due to _______
distance. - Answer✔Brake lag
It is accepted that too much heat caused by using your brakes too often can also cause: -
Answer✔Brake fade or failure
Repeatedly pressing and releasing (fanning) the brake pedal may result in: - Answer✔The loss of
brake air pressure
The brake system that applies and releases the brakes when the driver uses the brake pedal is the
________ brake system. - Answer✔Service
A slack adjuster's free play needs to be adjusted if it is more than about how many inches when
you pull hard on it? - Answer✔1 inch
The brake pedal in an air brake system: - Answer✔Controls the air pressure applied to put in the
brakes.
Under normal conditions in order to engage the parking brakes the driver must first: -
Answer✔Let the air out of the spring brakes.
Which of these is NOT a proper time to apply the parking brakes? - Answer✔If your brakes are
very hot.
What is the first thing you should do when a low air pressure warning comes on: - Answer✔Stop
and safety park as soon as possible.
The parking or emergency brake on a heavy vehicle can only be held in position by something
that cannot peak away, like: - Answer✔Spring Pressure
