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Flushing Procedure


Contamination in fluid of a hydraulic system is the primary cause of failure of a hydrostatic pump or motor. Before installing new major components, the system must be completely free of contamination. Changing the filter element and fluid is not enough to thoroughly clean the system. For this reason we have derived the following list of procedures that when followed step-by-step, will help to insure system cleanliness resulting in longer hydraulic component life.


This Is What You Do After Determining that the Hydraulic Component Needs to be Replaced:


(Remember: Keep It Clean)


Drain the hydraulic fluid from the lowest level in the system.


Remove the old hydraulic pumps and/or motors to be remanufactured.


Remove the filter elements.


Check all suction hoses for kinks, collapsed or deteriorating liners, or any other obstructions. Inspect all other hoses and fittings in the related system and replace as required.


Check the inside of the hydraulic reservoir for contamination (particles of steel or brass, sludge, dirt, etc.) and be sure that there are no obstructions in the suction or return system components.


Flush and blow out all hoses, pipes, tubing, and filter housings with a suitable cleaning solvent to remove any contamination.


After flushing out oil cooler with cleaning solvent, blow out with compressed air, and final flush with clean hydraulic oil.


Wipe out the inside of the hydraulic reservoir with a clean lint-free towel on reservoirs that allow access.


On reservoirs that do not allow access either replace reservoir with new or fabricate to gain access. Call with any questions on this.


Clean all pump and motor fittings to be replaced and install new "O-Rings" as required.


Replace all filter elements, gaskets, and seals as required.


Keep all hoses and fittings capped after cleaning to prevent contamination from entering the system.


Reinstall all pumps and motors



Filling, Purging, and Checking Pressures


Install hydrostat per manufacture’s recommendations.


Reconnect and tighten all lines removed during removal process being careful not to let debris in and enter hydraulic system. (Flush lines if not done previously).


Fill the pump case with new filtered oil through the upper most case drain port.


Fill the reservoir with new oil as per manufacture’s recommendations that meets OEM specifications ONLY.


Set the Control valve in neutral to prevent the equipment from engaging until the start-up procedures are completed.


Check all fittings and hose connections to be sure they are tight to prevent leakage.


Connect 0-600 psi gauges as per enclosed sheet with your remanufactured hydro.


Start the prime mover (engine) and allow it to run at idle for approximately 30 seconds and shut it off(except IH tractor which is checked while running). Check fluid level in reservoir, if low fill to proper level. Start the engine again, let idle, check fluid level in reservoir and fill to proper level.

Herrs Machine rebuilder, repairer, remanufacturer of hydro, hydrostatic transmission pumps and motors.


Hydraulic System

Flushing Procedure


Repair • Rebuild • Remanufacture • Exchange