Texas CDL Air Brakes Questions and
Answers Already Passed
What is the function of air brakes in a commercial vehicle?
✔✔Air brakes use compressed air to apply pressure to brake components, allowing the vehicle to
stop safely.
What is the purpose of the air compressor in an air brake system?
✔✔The air compressor supplies compressed air to the air brake system to power the brakes.
What does the air reservoir do in an air brake system?
✔✔The air reservoir stores compressed air for use in applying the brakes.
What is a safety feature of the air brake system in case of low air pressure?
✔✔A low air pressure warning light and buzzer activate to alert the driver when air pressure
drops below a safe level.
What happens when you release the parking brake on an air-braked vehicle?
1
,✔✔Releasing the parking brake allows compressed air to move into the brake chambers, making
the vehicle ready to move.
How can you check the air pressure build-up in an air brake system?
✔✔Start the engine and observe the air pressure gauges. The air pressure should build up to the
recommended level (usually 90-120 PSI).
What is the maximum air pressure level that most air brake systems should reach?
✔✔Air brake systems typically reach a maximum of 120 PSI.
How do you test the air brakes for proper operation?
✔✔You can test the air brakes by performing a "push and release" test or by applying the brake
pedal to ensure air pressure drops and the system functions properly.
What is the purpose of the dual air brake system?
✔✔The dual air brake system uses two separate air systems for safety, so if one system fails, the
other can still function.
What is a common cause of air brake failure?
2
, ✔✔Air leaks, low air pressure, or a malfunctioning compressor can lead to air brake failure.
What is the function of the brake shoe in an air brake system?
✔✔The brake shoe presses against the brake drum to create friction and stop the vehicle when
the brakes are applied.
How do you know if the air brake system has enough air pressure?
✔✔The air pressure should be at least 90 PSI when the vehicle is idling, and it should rise to the
recommended pressure after the engine is started.
What should you do if the air pressure warning light comes on while driving?
✔✔Immediately reduce speed and pull over to the side of the road to safely stop the vehicle, then
check the air pressure.
What is the air dryer’s role in the air brake system?
✔✔The air dryer removes moisture and contaminants from the compressed air before it enters
the air system.
What is the proper way to perform a parking brake test?
3
Answers Already Passed
What is the function of air brakes in a commercial vehicle?
✔✔Air brakes use compressed air to apply pressure to brake components, allowing the vehicle to
stop safely.
What is the purpose of the air compressor in an air brake system?
✔✔The air compressor supplies compressed air to the air brake system to power the brakes.
What does the air reservoir do in an air brake system?
✔✔The air reservoir stores compressed air for use in applying the brakes.
What is a safety feature of the air brake system in case of low air pressure?
✔✔A low air pressure warning light and buzzer activate to alert the driver when air pressure
drops below a safe level.
What happens when you release the parking brake on an air-braked vehicle?
1
,✔✔Releasing the parking brake allows compressed air to move into the brake chambers, making
the vehicle ready to move.
How can you check the air pressure build-up in an air brake system?
✔✔Start the engine and observe the air pressure gauges. The air pressure should build up to the
recommended level (usually 90-120 PSI).
What is the maximum air pressure level that most air brake systems should reach?
✔✔Air brake systems typically reach a maximum of 120 PSI.
How do you test the air brakes for proper operation?
✔✔You can test the air brakes by performing a "push and release" test or by applying the brake
pedal to ensure air pressure drops and the system functions properly.
What is the purpose of the dual air brake system?
✔✔The dual air brake system uses two separate air systems for safety, so if one system fails, the
other can still function.
What is a common cause of air brake failure?
2
, ✔✔Air leaks, low air pressure, or a malfunctioning compressor can lead to air brake failure.
What is the function of the brake shoe in an air brake system?
✔✔The brake shoe presses against the brake drum to create friction and stop the vehicle when
the brakes are applied.
How do you know if the air brake system has enough air pressure?
✔✔The air pressure should be at least 90 PSI when the vehicle is idling, and it should rise to the
recommended pressure after the engine is started.
What should you do if the air pressure warning light comes on while driving?
✔✔Immediately reduce speed and pull over to the side of the road to safely stop the vehicle, then
check the air pressure.
What is the air dryer’s role in the air brake system?
✔✔The air dryer removes moisture and contaminants from the compressed air before it enters
the air system.
What is the proper way to perform a parking brake test?
3
