CDL Air Brake Endorsement Exam 2025
Questions and Answers
It is not safe to drive a vehicle that has brake drums with cracks that are longer
than __ of the width of the friction area. - --CORRECT ANSWER--1/2
To correct a drive-wheel braking skid, you should: - --CORRECT ANSWER--Stop
braking and steer/counter steer
The air compressor stops pumping air at what psi? - --CORRECT ANSWER--125
Controlled braking: - --CORRECT ANSWER--Is used to keep vehicle braking in a
straight line
It is not safe to drive a vehicle that has brake drums (or discs) with cracks or that
are thinner than the manufacturer's specifications, generally this will be_ an inch. -
--CORRECT ANSWER--1/2
What do air brakes use to make the brakes work? - --CORRECT ANSWER--
Compressed air
Excessive use of the service brakes results in overheating which can lead to: - --
CORRECT ANSWER--Expansion of the brake drum
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, The air brake lag distance at 55 mph on dry pavement adds about __ feet. - --
CORRECT ANSWER--32 Feet
Before driving a truck or bus with a dual air brake system, the pressure in each air
brake system should be at least__psi. - --CORRECT ANSWER--100
The emergency brake system: - --CORRECT ANSWER--Uses parts of the service
and parking brake system to stop the vehicle in the event of a brake system failure
The parking or emergency brakes of trucks or buses can legally be held on by __
pressure. - --CORRECT ANSWER--Spring
The stop light switch: - --CORRECT ANSWER--Turns on the brake lights to
warn drivers behind you
The air supply pressure gauge shows how much pressure: - --CORRECT
ANSWER--is in the air tanks
Repeatedly pressing and releasing (fanning) the brake pedal may result in: - --
CORRECT ANSWER--The loss of air brake pressure
If the air compressor should develop a leak, what keeps the air in the tanks? - --
CORRECT ANSWER--The one way check valve
The driver must be able to see a warning before pressure in the service air tanks
falls below___psi. - --CORRECT ANSWER--60
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
Questions and Answers
It is not safe to drive a vehicle that has brake drums with cracks that are longer
than __ of the width of the friction area. - --CORRECT ANSWER--1/2
To correct a drive-wheel braking skid, you should: - --CORRECT ANSWER--Stop
braking and steer/counter steer
The air compressor stops pumping air at what psi? - --CORRECT ANSWER--125
Controlled braking: - --CORRECT ANSWER--Is used to keep vehicle braking in a
straight line
It is not safe to drive a vehicle that has brake drums (or discs) with cracks or that
are thinner than the manufacturer's specifications, generally this will be_ an inch. -
--CORRECT ANSWER--1/2
What do air brakes use to make the brakes work? - --CORRECT ANSWER--
Compressed air
Excessive use of the service brakes results in overheating which can lead to: - --
CORRECT ANSWER--Expansion of the brake drum
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, The air brake lag distance at 55 mph on dry pavement adds about __ feet. - --
CORRECT ANSWER--32 Feet
Before driving a truck or bus with a dual air brake system, the pressure in each air
brake system should be at least__psi. - --CORRECT ANSWER--100
The emergency brake system: - --CORRECT ANSWER--Uses parts of the service
and parking brake system to stop the vehicle in the event of a brake system failure
The parking or emergency brakes of trucks or buses can legally be held on by __
pressure. - --CORRECT ANSWER--Spring
The stop light switch: - --CORRECT ANSWER--Turns on the brake lights to
warn drivers behind you
The air supply pressure gauge shows how much pressure: - --CORRECT
ANSWER--is in the air tanks
Repeatedly pressing and releasing (fanning) the brake pedal may result in: - --
CORRECT ANSWER--The loss of air brake pressure
If the air compressor should develop a leak, what keeps the air in the tanks? - --
CORRECT ANSWER--The one way check valve
The driver must be able to see a warning before pressure in the service air tanks
falls below___psi. - --CORRECT ANSWER--60
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
