Patent ID: 7168530
Filing Date: 2007-01-30
Classification: F16D

Abstract:
1. An improved drum brake hydraulic cylinder comprising a conventional drum brake hydraulic cylinder body with at least one open end into a cylinder chamber with an axial center, a piston, a circular mounting face with an axial center, a first bleeder valve in the mounting face communicating with the cylinder chamber through a bleeder passage, said bleeder valve and passage located in a highest vertical position when the drum brake cylinder body is mounted to a drum brake backing plate on one side of a car, and a hydraulic fluid inlet communicating with the cylinder, wherein the improvement comprises: an O-ring disposed in an annular groove in the cylinder body adjacent the open end, wherein the O-ring contacts the piston to seal the cylinder chamber from contaminants entering from the at least one open end as the piston moves relative to the cylinder body, and wherein a single hydraulic chamber is formed by the piston between the open end and the cylinder chamber, the cylinder body and piston are made of a corrosion-resistant metal, the axial center of the cylinder chamber intersects the axial center of the circular mounting face, a second bleeder valve is disposed opposite the first bleeder valve in the circular mounting face in a lowest vertical position when the drum brake cylinder body is mounted to a drum brake backing plate on the one side of a car.