In a properly functioning dual air system, the pressure should hold from 85 psi to 100 psi for how long?

In a properly functioning dual air system, the pressure should hold from 85 psi to 100 psi for how long?

• A. 15 seconds
• B. 30 seconds
• C. 45 seconds
• D. 60 seconds

Answer: (C)

The main idea here is how quickly the air system charges to a usable level. In a properly functioning dual air system, the pressure should rise from 85 psi up to 100 psi in about 45 seconds. This time frame shows that the compressor and the lines are able to deliver enough air quickly enough for safe braking after the system has dropped to a low pressure.

If the rise takes noticeably longer than 45 seconds, it can indicate a problem such as a leak, a failing compressor, or worn components, which would delay brake release or application. Shorter times aren’t the target; 45 seconds is the standard benchmark used to verify healthy charging rate.