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Increase lift cylindar length?

Discussion in 'Fisher Engineering Discussion' started by es492420, Oct 10, 2014.

  1. es492420

    es492420 Junior Member
    Messages: 1

    I have an HD mm1 on a 2012 F250 and it doesn't lift as high as I would like. I don't want to shorten the chain because there's times there isn't enough slack to keep the plow floating on steep crests. Can I install a longer lift cylinder - like to a 12"? Seems like that would give me the lift without losing the slack. If so, would I have to upgrade the hydraulics at all? Or would it basically be a plug-n-play type of deal?

  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,389

    Don't they make long and short stacking stops. Might wanna look into that
  3. linckeil

    linckeil PlowSite.com Addict
    from CT
    Messages: 1,272

    there are a variety of pumps that fisher used on the MM1 setup over the years - a belt driven pump that mounted under the hood, a SEHP pump, and a insta-act pump. do you know which one you have?

    the SEHP was probably the most common for the MM1 and came with a 6" piston for 7 foot and under plows, and a 10" piston for 7.5 foot and larger plows. seeing as how you have a 8' plow, you should have the 10" pump and should have no problem. but if it some point in the plows life someone put a 6" pump on, then you could possibly be having the problem you describe.

    heres the 6" pump:

    heres the 10" pump:

    do you have either of these? seeing pictures of what you got would be helpful becuase in factory form, the problem you are describing should not be happening. makes me think the plow may have been altered in some way.
  4. kimber750

    kimber750 PlowSite Veteran
    Messages: 4,674

    Gotta agree with SS.

    Is it hitting the stops? Is the ram going all the way up? Pics of your setup would help.