A truck fails the build-up test, taking far longer than 45 seconds to go from 85 to 100 psi. What does that suggest?

• A.The brakes are adjusted too tightly
• B.The compressor cannot keep up, due to wear, drive problems, a restricted intake, or a significant leak
• C.The tanks are too large by design
• D.Slow build-up is normal for all diesels

Why

Build-up speed is a direct measure of compressor health against system demand. A slow result on the ground predicts a system that will fall behind during repeated braking on the road.

Manual topic: Air Brakes - Air Leakage and Brake Tests · From the Air Brakes practice bank (AB-091).

Practice this subject as a full test

More Leakage Rate Standards & Air Tests questions

• For the static leakage test, what are the starting conditions?
• With the engine off and brakes released, what is the maximum allowable leakage rate for a single vehicle?
• With the engine off and brakes released, what is the maximum allowable leakage rate for a combination vehicle?
• For the applied-brake leakage test, what does the driver do after making a full brake application?
• With the brakes fully applied and the engine off, what is the maximum allowable leakage for a single vehicle?