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CDL Air Brakes Questions and
Answers 100% Pass
Air loss in a straight truck or bus should not be more than how much PSI with the
engine off and the brakes on? - ✔✔3 PSI in one minute
To make an emergency stop with air brakes, using the stab braking method, you should
- ✔✔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? - ✔✔Low air pressure warning
signal
It is accepted that too much heat caused by using your brakes too often can also cause
what? - ✔✔brake to fade or fail
When is it ok to leave your truck unattended without applying the parking brakes and
choking the wheels? - ✔✔Never
Author: Katelyn Whitman. ©2025, All Rights Reserved.
, 2|Page
You should know that your brakes are fading when you have to do what? - ✔✔push
harder on the brake pedal to control your speed on a downgrade
The safety valve discharges automatically at what pressure? - ✔✔150
What is a dual airbrake system? - ✔✔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?
- ✔✔air pressure may drop to a low point while driving, requiring an emergency stop
How often should you drain air tanks? - ✔✔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? - ✔✔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? - ✔✔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? - ✔✔drop to a low point while driving
Author: Katelyn Whitman. ©2025, All Rights Reserved.
CDL Air Brakes Questions and
Answers 100% Pass
Air loss in a straight truck or bus should not be more than how much PSI with the
engine off and the brakes on? - ✔✔3 PSI in one minute
To make an emergency stop with air brakes, using the stab braking method, you should
- ✔✔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? - ✔✔Low air pressure warning
signal
It is accepted that too much heat caused by using your brakes too often can also cause
what? - ✔✔brake to fade or fail
When is it ok to leave your truck unattended without applying the parking brakes and
choking the wheels? - ✔✔Never
Author: Katelyn Whitman. ©2025, All Rights Reserved.
, 2|Page
You should know that your brakes are fading when you have to do what? - ✔✔push
harder on the brake pedal to control your speed on a downgrade
The safety valve discharges automatically at what pressure? - ✔✔150
What is a dual airbrake system? - ✔✔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?
- ✔✔air pressure may drop to a low point while driving, requiring an emergency stop
How often should you drain air tanks? - ✔✔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? - ✔✔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? - ✔✔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? - ✔✔drop to a low point while driving
Author: Katelyn Whitman. ©2025, All Rights Reserved.
