Air Brakes Test Questions
All 100% Correct Answers
Oil & water usually collect in compressed air tanks. If you do NOT have an automatic
tank drain, when should you drain the air tanks - Answers -✔✔ a. After every working
day.
b. After every four hours of service.
c. Once a week.
d. Every other week.
Correct Answer: After every working day.
Why drain water from the compressed air tanks? - Answers -✔✔ Water can freeze in
cold weather and cause brake failure.
The air brakes system for a straight truck or bus should not leak at a rate of more than
___ psi per minute with the engine off & the brakes released - Answers -✔✔ 2
To make an emergency stop with air brakes, using the stab braking method, you
should: - Answers -✔✔ 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: - Answers -✔✔ You have to push
harder on the brake pedal to control your speed on a downgrade.
If the air compressor should develop a leak, what keeps the air in the tanks? - Answers
-✔✔ The one way check valve
To check the brake slack on S-cam brakes you should park on - Answers -✔✔ Park on
level ground, chock the wheels, and release the parking brakes
The application pressure gauge shows how much air pressure you: - Answers -✔✔
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 - Answers -✔✔ 20
The safety valve is set to automatically reduce pressure at ___ psi - Answers -✔✔ 150
Your truck has a dual air system and one of the system loses its pressure, what will
happen - Answers -✔✔ 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: - Answers -✔✔ 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 within ____ seconds - Answers -
✔✔ 45
During normal driving, spring brakes are usually held back by: - Answers -✔✔ air
pressure
The air compressor stops pumping air at what psi - Answers -✔✔ 125
The driver must be able to see a warning before pressure in the service air tanks falls
below ___ psi - Answers -✔✔ 55 or 60
Excessive use of the service brakes results in overheating which can lead to - Answers
-✔✔ Expansion of the brake drums
The most common type of foundation brake found on heavy vehicles is the - Answers -
✔✔ S-cam drum brake
If you must make an emergency stop, brake so you: - Answers -✔✔ Can steer and
your vehicle stays in a straight line.
The braking power of the spring brakes - Answers -✔✔ Depends on the service brakes
being in adjustment
The air brakes lag distance at 55mph on dry pavement adds about ___ feet - Answers -
✔✔ 32 ft
Total stopping distance for air brakes is longer than that for hydraulic brakes due to ___
distance - Answers -✔✔ Brake lag
It is accepted that too much heat caused by using your brakes too often can also cause:
- Answers -✔✔ Brake fade or failure
Repeatedly pressing and releasing (fanning) the brake pedal may result in: - Answers -
✔✔ 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. - Answers -✔✔ service
A slack adjuster's free play need to be adjusted if it is more than about ___ how many
inches when you pull hard on it - Answers -✔✔ 1 inch
All 100% Correct Answers
Oil & water usually collect in compressed air tanks. If you do NOT have an automatic
tank drain, when should you drain the air tanks - Answers -✔✔ a. After every working
day.
b. After every four hours of service.
c. Once a week.
d. Every other week.
Correct Answer: After every working day.
Why drain water from the compressed air tanks? - Answers -✔✔ Water can freeze in
cold weather and cause brake failure.
The air brakes system for a straight truck or bus should not leak at a rate of more than
___ psi per minute with the engine off & the brakes released - Answers -✔✔ 2
To make an emergency stop with air brakes, using the stab braking method, you
should: - Answers -✔✔ 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: - Answers -✔✔ You have to push
harder on the brake pedal to control your speed on a downgrade.
If the air compressor should develop a leak, what keeps the air in the tanks? - Answers
-✔✔ The one way check valve
To check the brake slack on S-cam brakes you should park on - Answers -✔✔ Park on
level ground, chock the wheels, and release the parking brakes
The application pressure gauge shows how much air pressure you: - Answers -✔✔
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 - Answers -✔✔ 20
The safety valve is set to automatically reduce pressure at ___ psi - Answers -✔✔ 150
Your truck has a dual air system and one of the system loses its pressure, what will
happen - Answers -✔✔ 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: - Answers -✔✔ 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 within ____ seconds - Answers -
✔✔ 45
During normal driving, spring brakes are usually held back by: - Answers -✔✔ air
pressure
The air compressor stops pumping air at what psi - Answers -✔✔ 125
The driver must be able to see a warning before pressure in the service air tanks falls
below ___ psi - Answers -✔✔ 55 or 60
Excessive use of the service brakes results in overheating which can lead to - Answers
-✔✔ Expansion of the brake drums
The most common type of foundation brake found on heavy vehicles is the - Answers -
✔✔ S-cam drum brake
If you must make an emergency stop, brake so you: - Answers -✔✔ Can steer and
your vehicle stays in a straight line.
The braking power of the spring brakes - Answers -✔✔ Depends on the service brakes
being in adjustment
The air brakes lag distance at 55mph on dry pavement adds about ___ feet - Answers -
✔✔ 32 ft
Total stopping distance for air brakes is longer than that for hydraulic brakes due to ___
distance - Answers -✔✔ Brake lag
It is accepted that too much heat caused by using your brakes too often can also cause:
- Answers -✔✔ Brake fade or failure
Repeatedly pressing and releasing (fanning) the brake pedal may result in: - Answers -
✔✔ 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. - Answers -✔✔ service
A slack adjuster's free play need to be adjusted if it is more than about ___ how many
inches when you pull hard on it - Answers -✔✔ 1 inch
