1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

MM1 angling gets pushed back in

Discussion in 'Fisher Engineering Discussion' started by wheeler459, Feb 2, 2011.

  1. wheeler459

    wheeler459 Junior Member
    Messages: 3

    Hey all,

    I have a MM1 with under the hood pump on it. I went to stack some snow piles and I pushed with the plow angled. The plow pushed itself back straight. I could hear a creak sound as it did this. I pulled back and reangled again fine. Went forward and the plow angling got pushed straight again. Is it a valve gone bad or is one of the cylinders shot? Never had this happen.

  2. ElberyLandscape

    ElberyLandscape Junior Member
    from MA
    Messages: 9

    That happens to my mm2 also. from what i understand there is some sort of releif valve with in the pump that releases pressure at a certain point. it doesnt sound like theres anything broken just the hard packed snow causeing it to angle buy the force.
  3. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,214

    Something tells me you have a bad relief valve.This is how the system works.

    Hydraulic oil is trapped in the base end of the cylinders by the relief valves, the poppet check valve and solenoid cartridge valve S2.When the plow contacts an object, the force of the impact increases the hydraulic pressure in the base end of the cylinder.When the pressure exceeds the relief valve pressure setting, the relief valve opens allowing oil to flow to the base of the opposite cylinder.
  4. wheeler459

    wheeler459 Junior Member
    Messages: 3

    Is it something that I should be worried about? Is it something I should fix?
  5. John T

    John T Member
    Messages: 43

    are the relief valves adjustable? or different strengths/values?

    I found my old speedcast model G will do the same thing..

    I have found it is best to always do your heavy pushes straight on.
  6. wheeler459

    wheeler459 Junior Member
    Messages: 3

    @ John T

    That sounds true but in real life you cant always do it.
  7. aperfcrcle

    aperfcrcle Senior Member
    Messages: 343

    my mm1 does the same thing.. try to tighten up the angle quill... On my plow, its located in front of the box the angle lines run into. Just get a flat head driver and tighten it up.. It will still do it with really wet, heavy snow (or ice) but it wasnt as bad after I tightened it up. Hope this helps