King of the Highway: The Ultimate Big Rig & Semi-Truck Operations Challenge

What happens to the spring brakes if a semi-truck completely loses air pressure?

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Correct!

Incorrect!

Pneumatic pressure is required to compress the heavy internal steel springs of the brake chambers. If a complete leak occurs and air pressure drops below roughly 20-45 PSI, the springs instantly release, locking the brakes automatically.

What happens to the spring brakes if a semi-truck completely loses air pressure?

The brakes lock up automatically

The pedal becomes soft with zero braking

The engine is instantly forced to stall

The fifth wheel lock pin slides open

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