Michigan CDL - Air Brakes Practice Exam

How long should it take for air pressure in a dual air brake system to build from 85 to 100 psi?

1. 30 seconds

2. 45 seconds

3. 60 seconds

4. 90 seconds

The correct answer is: 45 seconds

In a dual air brake system, the standard expectation is that the air pressure should build from 85 psi to 100 psi within a specific time frame to ensure the system is functioning properly. The correct duration for this pressure increase is typically around 45 seconds. This timeframe is set to ensure that the braking system is responsive and maintains safety standards, as air brakes rely heavily on proper pressure levels for effective operation. If it takes longer than 45 seconds to reach 100 psi, this may indicate an issue with the air system, such as leaks or inadequate compressor performance, which could compromise the safety and efficiency of the vehicle. Regular maintenance and checks should be performed to ensure that the air brake system is efficient and compliant with these industry standards.