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Question:
Continue to fan off the air pressure by stepping on and off the brake pedal to reduce tank pressure. The tractor protection valve and parking brake valve should close (pop out) on a tractor-trailer combination vehicle and the parking brake valve should close (pop out) on other combination and single vehicle types when the air pressure falls to the manufacturer’s specification (20 – 45 psi). This will cause the spring brakes to come on. [Commercial Driver License Manual]
Comments
Alkam 2126
4 years ago
It a great app to study for your CDL tests
Cbow33
4 years ago
Great app
Livvy2u
4 years ago
Mom