CDL Air Brakes Questions & Answers
Air loss in a straight truck or bus should not be more than how much PSI with the
engine off and the brakes on? - Answers -✔✔ 3 PSI in one minute
To make an emergency stop with air brakes, using the stab braking method, you should
- Answers -✔✔ Brake as hard as you can
get off brakes when wheels lock
get back on brakes when wheels start rolling again
All vehicles with air brakes must have what signal? - Answers -✔✔ Low air pressure
warning signal
It is accepted that too much heat caused by using your brakes too often can also cause
what? - Answers -✔✔ brake to fade or fail
When is it ok to leave your truck unattended without applying the parking brakes and
choking the wheels? - Answers -✔✔ Never
You should know that your brakes are fading when you have to do what? - Answers -
✔✔ push harder on the brake pedal to control your speed on a downgrade
The safety valve discharges automatically at what pressure? - Answers -✔✔ 150
What is a dual airbrake system? - Answers -✔✔ 2 brake system
one operates front brakes
one operates back brakes
If air pressure is not built up within the correct amount of time, then what will happen? -
Answers -✔✔ air pressure may drop to a low point while driving, requiring an
emergency stop
How often should you drain air tanks? - Answers -✔✔ Daily
A slack adjusters free play needs to be adjusted if it is more than about how many
inches when you pull hard on it? - Answers -✔✔ 1 inch
In ideal conditions, a truck or bus with an air brake going at 55 mph would require a
stopping distance of how many feet? - Answers -✔✔ more than 300 feet
, If air pressure is not built up within the correct amount of time, then what will happen to
the air pressure? - Answers -✔✔ drop to a low point while driving
requiring an emergency stop
It is accepted that too much heat caused by using your brakes too often can also cause
what? - Answers -✔✔ Brake to fade or fail
What does the governor control? - Answers -✔✔ when air compressor will pump into
air storage tanks
To make an emergency stop with air brakes, using the stab braking method, you should
do what? - Answers -✔✔ Brake as hard as you can
get off brakes when wheels lock
get back on brakes when wheels start rolling
The driver must be able to see a low air pressure warning which comes on before
pressure in the service air tanks falls below what PSI? - Answers -✔✔ 60
The use of brakes on a long steep downgrade is only a supplement to the braking effect
of the engine - Answers -✔✔ True
The spring brakes used on the chambers in a straight truck will bring you to a stop when
air pressure drops below what PSI? - Answers -✔✔ 60
What do air brakes use to make the brakes work? - Answers -✔✔ Compressed Air
What can legally hold a parking or emergency brake in position for a truck, truck tractor,
or bus? - Answers -✔✔ Spring Pressure
When you put on the brakes by pushing down the brake pedal, what happens? -
Answers -✔✔ Air pressure is applied to the brake pads
Air loss in a straight truck or bus should not be more than what with the engine off and
the brakes on? - Answers -✔✔ 3 PSI in one Minute
What does the Emergency Brake System do? - Answers -✔✔ Uses part of the service
and parking brake system to stop the vehicle in the event of a brake system failure
The most common type of foundation brake found on heavy vehicles is what? - Answers
-✔✔ S-cam drum
Air loss in a straight truck or bus should not be more than how much PSI with the
engine off and the brakes on? - Answers -✔✔ 3 PSI in one minute
To make an emergency stop with air brakes, using the stab braking method, you should
- Answers -✔✔ Brake as hard as you can
get off brakes when wheels lock
get back on brakes when wheels start rolling again
All vehicles with air brakes must have what signal? - Answers -✔✔ Low air pressure
warning signal
It is accepted that too much heat caused by using your brakes too often can also cause
what? - Answers -✔✔ brake to fade or fail
When is it ok to leave your truck unattended without applying the parking brakes and
choking the wheels? - Answers -✔✔ Never
You should know that your brakes are fading when you have to do what? - Answers -
✔✔ push harder on the brake pedal to control your speed on a downgrade
The safety valve discharges automatically at what pressure? - Answers -✔✔ 150
What is a dual airbrake system? - Answers -✔✔ 2 brake system
one operates front brakes
one operates back brakes
If air pressure is not built up within the correct amount of time, then what will happen? -
Answers -✔✔ air pressure may drop to a low point while driving, requiring an
emergency stop
How often should you drain air tanks? - Answers -✔✔ Daily
A slack adjusters free play needs to be adjusted if it is more than about how many
inches when you pull hard on it? - Answers -✔✔ 1 inch
In ideal conditions, a truck or bus with an air brake going at 55 mph would require a
stopping distance of how many feet? - Answers -✔✔ more than 300 feet
, If air pressure is not built up within the correct amount of time, then what will happen to
the air pressure? - Answers -✔✔ drop to a low point while driving
requiring an emergency stop
It is accepted that too much heat caused by using your brakes too often can also cause
what? - Answers -✔✔ Brake to fade or fail
What does the governor control? - Answers -✔✔ when air compressor will pump into
air storage tanks
To make an emergency stop with air brakes, using the stab braking method, you should
do what? - Answers -✔✔ Brake as hard as you can
get off brakes when wheels lock
get back on brakes when wheels start rolling
The driver must be able to see a low air pressure warning which comes on before
pressure in the service air tanks falls below what PSI? - Answers -✔✔ 60
The use of brakes on a long steep downgrade is only a supplement to the braking effect
of the engine - Answers -✔✔ True
The spring brakes used on the chambers in a straight truck will bring you to a stop when
air pressure drops below what PSI? - Answers -✔✔ 60
What do air brakes use to make the brakes work? - Answers -✔✔ Compressed Air
What can legally hold a parking or emergency brake in position for a truck, truck tractor,
or bus? - Answers -✔✔ Spring Pressure
When you put on the brakes by pushing down the brake pedal, what happens? -
Answers -✔✔ Air pressure is applied to the brake pads
Air loss in a straight truck or bus should not be more than what with the engine off and
the brakes on? - Answers -✔✔ 3 PSI in one Minute
What does the Emergency Brake System do? - Answers -✔✔ Uses part of the service
and parking brake system to stop the vehicle in the event of a brake system failure
The most common type of foundation brake found on heavy vehicles is what? - Answers
-✔✔ S-cam drum
