Abstract: A master cylinder assembly in which the casing defines an annular seal groove defining a forward bore portion forwardly of the annular groove and a rearward bore portion rearwardly of the annular groove. The front end of the piston in the retracted position of the piston is received in the forward bore portion to provide total bearing support for the piston and axial grooves are provided in the forward bore portion to allow recuperative fluid to flow from the associated reservoir and through the axial grooves to the forward bore portion forwardly of the retreating piston.

Abstract: A concentric hydraulic clutch actuator including a coil spring arranged to be stressed in response to expansion and contraction of the actuator and including end portions which are bent radially inwardly and coact with circumferentially spaced lugs on the cylinder and on the piston to preclude relative rotation between the piston and cylinder in either direction of relative rotation. Relative rotation in one direction is inhibited by contact of the bent portion with one of the lugs and relative rotation in the other direction is inhibited by abutting engagement of the end face of the bent portions with respective lugs.

Abstract: The hydraulic clutch actuator for a motor vehicle of the concentric type in which the actuator is mounted concentrically around the transmission input shaft of the vehicle within the housing of the clutch. The actuator includes a housing structure defining a central quill shaft surrounding the input shaft of the vehicle and slidably supporting the hub portion of the bearing carrier and further defines an annular piston bore spaced radially outwardly from the quill shaft to define an annular bore between the piston bore and the quill shaft into which the rear end of the hub portion of the bearing carrier may move during the operation of the actuator so as to provide overlap as between the annular piston and the bearing carrier and minimize the axial dimension of the actuator. The preload spring is also positioned in the annular bore between the quill shaft and the piston bore so as to further optimize the compact packaging of the actuator.

Abstract: A hydraulic clutch actuator for a motor vehicle of the concentric type in which the actuator is mounted concentrically around the transmission input shaft of the vehicle within the housing of the clutch. The actuator includes a housing structure defining a central quill shaft surrounding the input shaft of the vehicle and slidably supporting the hub portion of the bearing carrier and further defines an annular piston bore spaced radially outwardly from the quill shaft to define an annular bore between the piston bore and the quill shaft into which the rear end of the hub portion of the bearing carrier may move during the operation of the actuator so as to provide overlap as between the annular piston and the bearing carrier and minimize the axial dimension of the actuator. The preload spring is also positioned in the annular bore between the quill shaft and the piston bore so as to further optimize the compact packaging of the actuator.

Abstract: A hydraulic cylinder and the method of making such hydraulic cylinder of a tubular sleeve and a housing of dissimilar material cast or molded around the sleeve. The sleeve is provided at least at one end with a portion projecting into the material of the housing, such projection being preferably in the form of an annular bead with a corresponding internally disposed groove. The other end of the sleeve has an internally radially projecting flange projecting into the material of the housing, and the elastomeric O-ring is disposed at the junction between the internal surface of the flange and the surface of the sleeve bore to provide a seal for the pressure end of the cylinder.