CDL Air Brakes Exam 2025 Questions
and 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? - --CORRECT ANSWER--3 PSI in one minute
To make an emergency stop with air brakes, using the stab braking method, you
should - --CORRECT ANSWER--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? - --CORRECT ANSWER--Low
air pressure warning signal
It is accepted that too much heat caused by using your brakes too often can also
cause what? - --CORRECT ANSWER--brake to fade or fail
When is it ok to leave your truck unattended without applying the parking brakes
and choking the wheels? - --CORRECT ANSWER--Never
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, You should know that your brakes are fading when you have to do what? - --
CORRECT ANSWER--push harder on the brake pedal to control your speed on a
downgrade
The safety valve discharges automatically at what pressure? - --CORRECT
ANSWER--150
What is a dual airbrake system? - --CORRECT ANSWER--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? - --CORRECT ANSWER--air pressure may drop to a low point while
driving, requiring an emergency stop
How often should you drain air tanks? - --CORRECT ANSWER--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? - --CORRECT ANSWER--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? - --CORRECT ANSWER--more than 300
feet
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
and 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? - --CORRECT ANSWER--3 PSI in one minute
To make an emergency stop with air brakes, using the stab braking method, you
should - --CORRECT ANSWER--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? - --CORRECT ANSWER--Low
air pressure warning signal
It is accepted that too much heat caused by using your brakes too often can also
cause what? - --CORRECT ANSWER--brake to fade or fail
When is it ok to leave your truck unattended without applying the parking brakes
and choking the wheels? - --CORRECT ANSWER--Never
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, You should know that your brakes are fading when you have to do what? - --
CORRECT ANSWER--push harder on the brake pedal to control your speed on a
downgrade
The safety valve discharges automatically at what pressure? - --CORRECT
ANSWER--150
What is a dual airbrake system? - --CORRECT ANSWER--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? - --CORRECT ANSWER--air pressure may drop to a low point while
driving, requiring an emergency stop
How often should you drain air tanks? - --CORRECT ANSWER--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? - --CORRECT ANSWER--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? - --CORRECT ANSWER--more than 300
feet
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
