Free CDL Air Brake Parking and Emergency Brakes Questions and Answers

Question 1

What activates the parking brakes in an air brake system?

Accepted Answer

Spring pressure when air is removed.

Answer

Hydraulic pressure.

Answer

Air pressure from the service system.

Answer

The foot brake pedal.

Question 2

When should you use parking brakes?

Accepted Answer

Every time you park the vehicle, unless brakes are hot or in freezing weather.

Answer

Only when parking on a hill.

Answer

Only when parking in a flat area.

Answer

During emergency braking situations.

Question 3

What should you do if your parking brakes won’t release due to frozen brake components?

Accepted Answer

Use a heater or other method to warm the brakes.

Answer

Drive slowly until they release.

Answer

Pour hot water over the frozen parts.

Answer

Use the emergency brake to override the parking brake.

Question 4

When do spring brakes automatically engage in a failure situation?

Accepted Answer

When air pressure drops to 20-45 psi.

Answer

When air pressure drops below 60 psi.

Answer

When the driver presses the brake pedal fully.

Answer

When the ABS system is activated.

Question 5

Can spring brakes and service brakes be applied simultaneously?

Accepted Answer

No, it can damage the brake system.

Answer

Yes, to maximize braking force.

Answer

Only in emergency braking situations.

Answer

Only if the parking brake valve is manually released.