CDL AIR BRAKES EXAM 2025
QUESTIONS AND ANSWERS
When your vehicle is empty, start braking: - --CORRECT ANSWER--Sooner than
when loaded
Modern air brake systems combine three different systems. They are the service
brakes, the parking brakes and the : - --CORRECT ANSWER--Emergency brake
What does the air compressor governor do? - --CORRECT ANSWER--It controls
when air is pumped into the air tanks
Oil and water that collects in air tanks can make brakes fail. If you do not have
automatic tank drains, when should you drain the air tanks? - --CORRECT
ANSWER--Every day
If your vehicle has an alcohol evaporator, why is it there? - --CORRECT
ANSWER--To reduce the risk of ice in air brake valves in cold weather
The brake pedal in an air brake system: - --CORRECT ANSWER--Controls the air
pressure applied to put on brakes
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, If your vehicle has an alcohol evaporator, everyday during cold weather what
should you do? - --CORRECT ANSWER--Check and fill the alcohol level
Why drain water from compressed air tanks? - --CORRECT ANSWER--Water can
freeze in cold weather and cause brake failure
Vehicle with air brakes must have: - --CORRECT ANSWER--An air pressure
gauge to show the pressure available for braking
The driver must be able to see a warning light that is given when air pressure in the
service tanks falls bellow: - --CORRECT ANSWER--60 PSI
During Normal driving, parking and emergency brakes are usually held back by? - -
-CORRECT ANSWER--Air pressure
The parking and emergency brake on a heavy vehicle can only be held in position
by something that can not leak away such as: - --CORRECT ANSWER--Spring
pressure
What does the application pressure gauge shows you? - --CORRECT ANSWER--
It shows how much air pressure you are applying to the brakes
Front brake limiting valves are used to: - --CORRECT ANSWER--Reduce the
chance of front wheel skids
If your truck or bus has dual parking control valves, you can use pressure from a
separate tank for what purpose? - --CORRECT ANSWER--To release the
emergency parking brakes to move a short distance
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
QUESTIONS AND ANSWERS
When your vehicle is empty, start braking: - --CORRECT ANSWER--Sooner than
when loaded
Modern air brake systems combine three different systems. They are the service
brakes, the parking brakes and the : - --CORRECT ANSWER--Emergency brake
What does the air compressor governor do? - --CORRECT ANSWER--It controls
when air is pumped into the air tanks
Oil and water that collects in air tanks can make brakes fail. If you do not have
automatic tank drains, when should you drain the air tanks? - --CORRECT
ANSWER--Every day
If your vehicle has an alcohol evaporator, why is it there? - --CORRECT
ANSWER--To reduce the risk of ice in air brake valves in cold weather
The brake pedal in an air brake system: - --CORRECT ANSWER--Controls the air
pressure applied to put on brakes
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, If your vehicle has an alcohol evaporator, everyday during cold weather what
should you do? - --CORRECT ANSWER--Check and fill the alcohol level
Why drain water from compressed air tanks? - --CORRECT ANSWER--Water can
freeze in cold weather and cause brake failure
Vehicle with air brakes must have: - --CORRECT ANSWER--An air pressure
gauge to show the pressure available for braking
The driver must be able to see a warning light that is given when air pressure in the
service tanks falls bellow: - --CORRECT ANSWER--60 PSI
During Normal driving, parking and emergency brakes are usually held back by? - -
-CORRECT ANSWER--Air pressure
The parking and emergency brake on a heavy vehicle can only be held in position
by something that can not leak away such as: - --CORRECT ANSWER--Spring
pressure
What does the application pressure gauge shows you? - --CORRECT ANSWER--
It shows how much air pressure you are applying to the brakes
Front brake limiting valves are used to: - --CORRECT ANSWER--Reduce the
chance of front wheel skids
If your truck or bus has dual parking control valves, you can use pressure from a
separate tank for what purpose? - --CORRECT ANSWER--To release the
emergency parking brakes to move a short distance
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
