Arizona Air Brakes CDL Practice Test

To check the air compressor governor "cut in" and "cut out" pressures...

1. Run the engine at a fast idle

2. Step on and off the brake to reduce tank pressure

3. Monitor the air pressure gauge

4. All of the above

The correct answer is: All of the above

To determine the air compressor governor's "cut in" and "cut out" pressures, several procedures must be followed. Running the engine at a fast idle helps facilitate the necessary conditions for air pressure to build up in the system. When the engine is at this speed, the air compressor operates more efficiently, allowing the governor to activate at the designated cut-in pressure. Stepping on and off the brake reduces the tank pressure, which is essential as it allows you to observe the governor's performance when the pressure is low. This action brings the system to a lower pressure, enabling you to see at what point the governor kicks in to start the compressor again, reestablishing air pressure up to the cut-out level. Monitoring the air pressure gauge is crucial to visually verify the actual pressures at which these events occur. This tool provides real-time feedback and confirms that the readings match the manufacturer’s specifications for cut-in and cut-out pressures. All of these steps are important in assessing the functionality of the air compressor governor within the air brake system. Thus, taking all of these actions together ensures a comprehensive check of the governor’s performance, confirming its ability to maintain adequate air pressure in the system.