Michigan CDL - Air Brakes Practice Exam

What is the maximum leakage rate for a triple combination vehicle during an applied leakage test?

1. 4 psi in a minute

2. 6 psi in a minute

3. 10 psi in a minute

4. 8 psi in a minute

The correct answer is: 6 psi in a minute

The maximum leakage rate for a triple combination vehicle during an applied leakage test is 6 psi in a minute. This standard is established to ensure that vehicles are safe and functioning correctly. A combination vehicle, consisting of a tractor and two trailers, has a complex braking system. It’s critical to minimize air loss from the system to maintain effective braking performance. An applied leakage test involves applying the brakes and monitoring the air pressure drop over a specific period. A leakage rate exceeding 6 psi could indicate that there are air leaks in the system, which may compromise braking efficiency and overall vehicle safety. Keeping to this standard helps ensure that equipment is maintained to prevent potential failures while on the road, promoting the safety of the driver, the vehicle, and others on the road.