What does the safety valve on an air brake system do?

a.Opens at 60 PSI to warn the driver

b.Opens at 150 PSI to protect the tank from over-pressurization

c.Closes at 125 PSI to stop air flow

d.Releases air when the brake pedal is pressed

Explanation

The safety valve is installed in the first tank the air compressor pumps air into. It protects the tank and the system from too much pressure by automatically opening (popping off) if pressure reaches 150 PSI.

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About the CDL Exam

The CDL (Commercial Driver License) exam tests your knowledge of commercial driving rules, safety procedures, and vehicle operation. You must score 80% or higher to pass the written knowledge test. The exam covers general knowledge, air brakes, combination vehicles, and various endorsements.

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