Arizona Air Brakes CDL Practice Test

At what pressure does the governor stop pumping air, reaching the "cut out" level?

1. 200 psi

2. 125 psi

3. 175 psi

4. 225 psi

The correct answer is: 125 psi

The governor is a critical component of an air brake system that regulates the air pressure in the tanks. When the air pressure in the brake system reaches a predetermined level, referred to as the "cut out" level, the governor ceases the operation of the air compressor. For most commercial vehicles, this level is typically set at 125 psi. This means that when the air system builds pressure up to 125 psi, the governor stops the compressor from pumping air, preventing over-pressurization and potential damage to the system. Maintaining the proper cut-out pressure is essential for the safe operation of air brake systems, ensuring that they function effectively without the risk of failure due to excessive pressure. Understanding the cut-out pressure helps drivers recognize the importance of monitoring their air pressure and maintaining their braking systems in optimal working order.