This spring is an original component used within the hydraulic system of the host machine. It provides a controlled return force for a valve spool or actuator piston, maintaining proper system pressure and timing. A spring that has lost its tension or has taken a set will cause sluggish valve response or incomplete spool return, leading to erratic hydraulic function. The spring is wound to the original wire diameter and free length, which matches the installed height of the housing cavity so that preload is correct without shimming. On reinstallation, verify the spring seats squarely in its pocket and that the retaining cap or plug is torqued to specification.