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Draining Under Hood pump

Discussion in 'Fisher Engineering Discussion' started by Tomas090, Dec 22, 2008.

  1. Tomas090

    Tomas090 Member
    from Maine
    Messages: 63

    Most of the answers I receive regarding my painfully slow Fisher seem to relate to dirty or contaminated fluid

    When I installed plow this season, I put in new fluid but plow had sat in mud and rain for many years

    What is the proper procedure for completely driang the under hood pump, rams and such to make sure all "bad" fluid is gone and air is removed?


    I have no special tools so the "simplest" method is appreciated
  2. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    I have an older Fisher belt-drive pump, too.

    Annual flushes are the recommended procedure for removing old fluid.

    If I were you, here's what I would do.

    1) Suction as much old fluid out of your pump as you can (not absolutely necessary but helpful)

    2) change filter (or install one if you don't have it--Fisher sells kit) on low-pressure return line

    3) unthread hoses from angle rams, manually angle plow back and forth, collapsing each cylinder in turn, to push out old fluid from cylinders (disassemble, clean, and replace packings of cylinders if you want to be thorough, but not necessary unless you have leaking)

    4) fill reservoir with fresh ATF

    5) hook up one angle ram hose to its coupling on the headgear (to the end of one of the hoses running from the valve body, in other words), insert the other end into an empty gallon container

    6) fire up the motor, move your control lever to the side (as if you were going to angle the blade), and flush out about a pint of fluid, or until you see fresh clean fluid coming out; then do the same with the other hose (top off the fluid first!); finally, unthread the lift ram hose from the swivel fitting at the bottom of the lift ram, insert the hose into your gallon container, and flush that out.

    7) You should now have nothing but clean fluid in your system. Mount the blade, hook up all the hoses and bleed the system of air (to do this, I just lift the blade up, attach the carrying chain, lower the blade so that it's off the ground but the lift cylinder is fully collapsed, and then angle all the way to one side, top off fluid, angle all the way to the other side, top off fluid, and then angle back and forth a few times. Check fluid one last time when you're done.

    8) Make sure there are no leaks anywhere.

    It goes without saying that you replace any worn hoses, check your drive belt and replace if worn, adjust it properly, etc.
  3. Tomas090

    Tomas090 Member
    from Maine
    Messages: 63

    Thanks, much appreciated and informative