Commercial Driving Air Brakes

Question 1

What is the purpose of the air compressor in an air brake system?

Accepted Answer

To pump air into storage tanks to provide the energy for braking

Answer

To cool the brakes

Answer

To inflate the tires

Answer

To power the horn

Question 2

At what PSI should the low air pressure warning activate?

Accepted Answer

60 PSI

Answer

40 PSI

Answer

80 PSI

Answer

100 PSI

Question 3

What happens when the air pressure drops too low in the brake system?

Accepted Answer

The spring brakes automatically apply, bringing the vehicle to a stop

Answer

The brakes release completely

Answer

The engine shuts off

Answer

Nothing, the brakes work the same

Question 4

What is the purpose of the air brake system's governor?

Accepted Answer

To control the air compressor by starting it when pressure drops and stopping it when pressure reaches the maximum

Answer

To control the speed of the vehicle

Answer

To regulate brake pedal pressure

Answer

To measure tire pressure

Question 5

What is 'brake lag' in air brake systems?

Accepted Answer

The delay between pressing the brake pedal and the brakes actually applying, typically about 0.5 seconds

Answer

A braking defect

Answer

The sound brakes make when applied

Answer

The distance traveled while braking

Question 6

What is the air brake cut-in and cut-out pressure range?

Accepted Answer

100-125 PSI

Answer

50-75 PSI

Answer

80-100 PSI

Answer

125-150 PSI