Michigan CDL - Air Brakes Practice Exam

A rapid drop in the air pressure gauge reading is a clear indication of a leak in the air brake system. This occurs because, in a properly functioning system, air pressure should remain stable when the vehicle is not being operated. If there is a leak, air escapes from the system which results in a noticeable decrease in pressure.

Identifying a leak is critical for maintaining safety, as insufficient air pressure can lead to brake failure. The air brakes require a specific pressure range to function effectively, and any significant drop below this threshold compromises brake performance. As a driver, being alert to changes in air pressure readings can help in early detection of potential problems, allowing for timely maintenance and repair.

Other signs, such as unusual noises or vibrations, may suggest various issues but are not definitive signals of an air leak specifically. A sudden increase in air pressure could indicate other system behaviors, and while unusual sounds may point to a problem, they do not directly correlate to air pressure fluctuations that indicate leaks.