A leaking shaft seal in an older Yuken pump is the symptom of a deeper problem. Internal bypass leakage creates a high case drain flow and an increased case pressure, which results in a shaft seal “blowing out”. Simply replacing the shaft is a temporary fix of the symptom, not the root cause. S&T repairs Yuken hydraulic pumps by overhauling the internal pumping action and control action eliminating the internal bypass.
By calibrating control valves with input machine command signals and hydraulic output we are able to set your pump up for the machine it operates on. Idle pressure, max volume stop, a given flow and pressure at a specific command are all tested, documented and included with your repaired pump for reference during installation and set up.
Yearly oil changes are encouraged to ensure your hydraulic pump is operating with oil that is clean and providing the lubricity required for internal moving parts. Oil particulate testing is a good indication of which parts are declining and when to fix them. A flow meter installed on your case drain line is an inexpensive way to monitor the health of your hydraulic pump.