Remove the filter from the Servovalve by using a 3/16-inch Allen wrench to unwind the screws. After the four screws are removed, take off the filter cover. Carefully remove the filter cartridge from the port. Inspect for any leaking fluid or possible filter contamination.
Install the O-ring from the old filter into the new filter cartridge by carefully placing it into the elements recess. Place the new filter cartridge back into the filter port. Replace the filter cover and use the Allen wrench again to fix the four screws back into place.
Check for a high null bias by installing the Servovalve on a test fixture. Apply system pressure and check for any components drifting in the Servovalve. If this occurs, use a wrench to adjust the mechanical null of the Servovalve. Keep adjusting until the drifting ceases.
Place the Servovalve back on the test fixture and attach an electrical lead to it. Run a current through the Servovalve to check that all system requirements are now met.