Texas CDL Air Brakes EXAM 2025
QUESTIONS AND ANSWERS
Air brake systems combine what three different systems? - ANS Service brakes, parking
brakes and emergency brakes.
When should you drain the air tanks? - ANS After every working day.
Why drain water from the compressed air tanks? - ANS Water can freeze in cold weather and
cause brake failure.
Air brake equipped vehicles must have: - ANS A supply pressure gauge and warning signal
when psi drops below 60.
What can legally hold a parking or emergency brake in position for a truck, truck tractor or bus?
- ANS Spring pressure.
What makes the total stopping distance for air brakes longer than that for hydraulic brakes? -
ANS Brake lag distance.
The first thing you should do when the low air pressure warning comes on? - ANS Stop and
safely park ASAP.
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Page
@COPYRIGHT BRAINBARTER 2025/2026
, The braking power of the spring brakes: - ANS Depends on the adjustment of the service
brakes.
The air compressor governor controls what? - ANS When air is pumped into the air tanks.
The application pressure gauge shows the driver how much pressure: - ANS Is being applied
to the brakes.
When you apply pressure to the brake pedal, you are... - ANS Pushing against a spring and
against air pressure to the brakes.
The air compressor is connected to the engine through... - ANS Gears or a V-belt
Which type of brake is the most common in commercial vehicles? - ANS S-cam brake
An application pressure gauge... - ANS Shows how much air pressure you are applying to the
brakes.
All vehicles with air brakes are required to have a low pressure warning signal. This could be... -
ANS A red light, wig wag mechanical arm or a buzzer.
To test service brakes you should... - ANS Release the parking brake, move forward slowly
and depress brakes.
Stab braking occurs when you... - ANS 1. Press on a brake pedal as hard as you can. 2.
Release the brakes when the wheels lock up. 3. Apply the brakes when the wheels start rolling.
Air brakes take longer to stop than hydraulic brakes because... - ANS It takes longer for the
2
air to flow through the lines.
Page
@COPYRIGHT BRAINBARTER 2025/2026
QUESTIONS AND ANSWERS
Air brake systems combine what three different systems? - ANS Service brakes, parking
brakes and emergency brakes.
When should you drain the air tanks? - ANS After every working day.
Why drain water from the compressed air tanks? - ANS Water can freeze in cold weather and
cause brake failure.
Air brake equipped vehicles must have: - ANS A supply pressure gauge and warning signal
when psi drops below 60.
What can legally hold a parking or emergency brake in position for a truck, truck tractor or bus?
- ANS Spring pressure.
What makes the total stopping distance for air brakes longer than that for hydraulic brakes? -
ANS Brake lag distance.
The first thing you should do when the low air pressure warning comes on? - ANS Stop and
safely park ASAP.
1
Page
@COPYRIGHT BRAINBARTER 2025/2026
, The braking power of the spring brakes: - ANS Depends on the adjustment of the service
brakes.
The air compressor governor controls what? - ANS When air is pumped into the air tanks.
The application pressure gauge shows the driver how much pressure: - ANS Is being applied
to the brakes.
When you apply pressure to the brake pedal, you are... - ANS Pushing against a spring and
against air pressure to the brakes.
The air compressor is connected to the engine through... - ANS Gears or a V-belt
Which type of brake is the most common in commercial vehicles? - ANS S-cam brake
An application pressure gauge... - ANS Shows how much air pressure you are applying to the
brakes.
All vehicles with air brakes are required to have a low pressure warning signal. This could be... -
ANS A red light, wig wag mechanical arm or a buzzer.
To test service brakes you should... - ANS Release the parking brake, move forward slowly
and depress brakes.
Stab braking occurs when you... - ANS 1. Press on a brake pedal as hard as you can. 2.
Release the brakes when the wheels lock up. 3. Apply the brakes when the wheels start rolling.
Air brakes take longer to stop than hydraulic brakes because... - ANS It takes longer for the
2
air to flow through the lines.
Page
@COPYRIGHT BRAINBARTER 2025/2026
