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What does the tractor protection valve protect, and how does it do it?
- A.It keeps trailer lights from draining the battery
- B.It protects the paint from trailer swing damage
- C.It closes and keeps air in the tractor if the trailer breaks away or develops a major air leak
- D.It stops cargo from shifting forward
Correct answer
C. It closes and keeps air in the tractor if the trailer breaks away or develops a major air leak
Why
If trailer air is lost suddenly, the tractor protection valve shuts off the trailer supply line and preserves tractor air for braking. Without it, a breakaway could drain the tractor tanks and leave the driver with almost no brakes.
Manual topic: Air Brakes - Tractor Protection Valve · From the General Knowledge practice bank (GK-110).