CDL Air Brakes Practice Test 1

Question 1

What type of air do air brakes use?

Accepted Answer

Compressed air

Answer

Air brake systems operate by using compressed air, which is stored in tanks and then released to activate the brake components. An air compressor builds up the pressure, and when the driver presses the brake pedal, this compressed air is directed to the brake chambers, applying force to stop the vehicle.

Question 2

What are the three types of brake systems used in a commercial vehicle air brake system?

Accepted Answer

Service brake, parking brake, emergency brake

Answer

Commercial vehicles with air brakes utilize three distinct braking systems. The service brake is used for normal stopping, the parking brake holds the vehicle stationary when parked, and the emergency brake system uses parts of the service and parking brake systems to stop the vehicle in case of a service brake failure. These systems work together to ensure safe operation and parking.

Question 3

What is the name of the device that pumps air into the air storage tanks?

Accepted Answer

Air compressor

Answer

The air compressor is a vital component of an air brake system, responsible for drawing in air from the atmosphere and compressing it. This compressed air is then stored in the air tanks, providing the necessary pressure to operate the vehicle's brakes and other air-powered accessories.

Question 4

What is the alcohol evaporator's primary purpose?

Accepted Answer

Put alcohol into the air system

Answer

An alcohol evaporator, found in some older air brake systems, is designed to inject alcohol vapor into the air lines. This alcohol helps prevent moisture in the air system from freezing during cold weather, which could otherwise cause brake components to malfunction and lead to brake failure.

Question 5

What psi level is the safety relief valve set to open at?

Accepted Answer

150 psi

Answer

The safety relief valve is a crucial safety device in the air brake system, designed to protect the air tanks and other components from excessive pressure. It is typically set to open and release air if the pressure in the system exceeds 150 psi, preventing damage or rupture of the air tanks.

CDL Practice Test

CDL Practice Test

CDL Air Brakes Practice Test 1