FREE CDL Air Brake Pre-Trip Inspection Questions and Answers

Question 1

When inspecting the air brake system during a pre-trip, what should you check regarding the air compressor?

Accepted Answer

All of the above.

Answer

That it turns off and on automatically at specific pressures.

Answer

That it has no visible leaks or damage.

Answer

That it is properly secured and operational.

Question 2

How do you check for leaks in the air brake system?

Accepted Answer

Apply full brake pressure, turn off the engine, release the brakes, and watch the pressure gauge.

Answer

Listen for hissing sounds while the engine is running.

Answer

Pump the brakes until air pressure drops below 20 psi.

Answer

Activate the parking brake and check for pressure changes.

Question 3

What is the proper way to test the low air pressure warning system?

Accepted Answer

Press the brake pedal repeatedly until the warning light or buzzer activates.

Answer

Wait until air pressure drops to zero.

Answer

Turn off the engine and listen for a warning sound.

Answer

Check it only after driving a short distance.

Question 4

How do you test the parking brake during a pre-trip inspection?

Accepted Answer

By applying the parking brake and gently pulling against it in a low gear.

Answer

By listening for air leaks when the parking brake is engaged.

Answer

By checking the dashboard for warning lights.

Answer

By applying the service brakes and watching the air pressure gauge.

Question 5

How do you perform the air pressure build-up test?

Accepted Answer

Ensure the compressor builds pressure from 85 to 100 psi within 45 seconds.

Answer

Pump the brakes until the pressure drops below 50 psi.

Answer

Observe the air tanks draining water and oil during pressure build-up.

Answer

Accelerate the engine to maximum RPM and check the gauge.