What is the cut-out pressure in pounds per square inch (psi) for air brakes on a school bus?

The cut-out pressure for air brakes on a school bus is set at 120 psi. This standard is significant because it pertains to the point at which the air compressor will stop pumping air into the storage tanks once the designated pressure level is reached. Maintaining proper cut-out pressure is crucial for the safe operation of air brake systems, as it ensures that the brakes have sufficient air pressure to function effectively and reliably.

Understanding this pressure level helps drivers and bus operators monitor the air brake system's functionality. If the pressure were to drop below this cut-out threshold, it could indicate a problem in the air system, potentially compromising the safety of the bus and its passengers. That's why it's important for school bus drivers to be aware of and regularly check the air brake system, ensuring that the cut-out pressure aligns with the mandated 120 psi for optimal performance.