What happens when a proportioning valve is failed?
What happens when a proportioning valve is failed? On front to rear split hydraulic systems a failed proportioning valve should cause both rear wheels to lockup under panic braking – unless one rear brake has a condition that will prevent this (i.e. severely out of adjustment or seized wheel cylinder). How does the proportioning valve work in a panic stop? All vehicles, those with rear drum and rear disc brakes, will experience weight transfer during a panic stop. When weight is taken off the rear wheels during a panic stop the tendency for the rear brakes to lockup will increase....