Quote
A valve for use in vehicle hydraulic brake systems for the purpose of limiting the rear wheel brake pressure relative to the front wheel brake pressure in order to reduce the potential for premature rear wheel lock. The valve includes a proportioning piston which operates to limit the fluid pressure delivered to the rear wheel brakes and an inertia member which senses changes in vehicle loading. When a vehicle is fully loaded, the inertia member remains in a position where it will disable the proportioning piston in its open position and, consequently, the rear wheel brake pressure will be equal to the front wheel brake pressure. When the same vehicle is unloaded, the inertia member moves in response to deceleration to a position where it will not disable the proportioning piston so that the rear wheel brake pressure will be reduced relative to the front wheel brake pressure.
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