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MM1 all hydraulic lift issue

Discussion in 'Fisher Engineering Discussion' started by thatlittleguy?, Jan 2, 2011.

  1. thatlittleguy?

    thatlittleguy? Member
    Messages: 34

    I have a 7.5 foot MM1 with the belt driven pump under the hood. The problem I'm having only occurs after I've been plowing for an hour or so. After some time when I go to raise the blade it doesn't move, or it moves slowly until I get the engine RPM's up. This doesn't happen when I first start the truck, or when I do the first few passes.

    I have no leaks
    Fluid level is correct
    New fluid 3 weeks ago

    Any thoughts?

    Thanks
     
  2. jaybird

    jaybird Member
    Messages: 40

    pump is tired. when the fluid heats up it gets thinner so the gears on the pump which are probably worn has a harder time pumping the thin fluid. when the fluid is cold its thicker. thats why when you rev it engine it moves, pumps working faster and trying to work harder
     
  3. thatlittleguy?

    thatlittleguy? Member
    Messages: 34

    is there a fix for this, besides replacing the pump?
     
  4. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    not realy.
     
  5. Don't want to insult you but is the belt nice and tight?
     
  6. thatlittleguy?

    thatlittleguy? Member
    Messages: 34

    not insulting, I know sometimes people overlook simple stuff. But yes, unfortunately the belt is tight
     
  7. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    watch ebay. new old stock pumps pop up from time to time for around 125-175.

    new pump would be my fix. i would never like to go to electric. read about all the problems here wih salt/water/dirt/corrosion.
     
  8. jaybird

    jaybird Member
    Messages: 40

    you should be looking for part # A2311