Wilwood 10lb residual pressure valves retain a minimum brake line pressure to help eliminate excessive pedal travel in drum brake systems.
The 10lb valve is used in drum brake applications where the master cylinder is mounted below the horizontal plane of the wheel cylinders and fluid drain back occurs from gravity and vibration, thereby causing excessive wheel cylinder piston retraction and a longer brake pedal stroke.
The minimal 10lb residual pressure prevents fluid from flowing back without causing the brakes to drag. With drum brakes, a 10lb valve is used to compensate for return spring tension and maintain wheel cylinder sealing in the drums.
Residual Pressure Valves are made from billet aluminum and color coded for easy identification.