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MM1 - blade drops / fluid drained while driving

Discussion in 'Fisher Engineering Discussion' started by jjorgensen52, Jan 20, 2012.

  1. jjorgensen52

    jjorgensen52 Junior Member
    from NH
    Messages: 3

    New here, looking for some assistance. I have a 6' 6" MM1 mounted on my '69 Chevy pickup (I think it was originally for a small Toyota). I bought the plow last year, cleaned it up, changed the fluid and redid a bunch of wiring. Worked great. I've since had to replace both angle cylinder lines.

    Today I was driving between locations on a state highway, 55mph, and with the controller off, and the plow lowered itself. I turned the controller on and raised it, but it dropped immediately and wouldn't lift again. Pulled over and the entire bottom of the pump housing was covered with oil (as well as the front of my truck, the back of the blade, etc...). Used the carry chain to bring it home.

    I can't see a clear source of leakage, other than it is definitely at the bottom of the pump housing. Looking at the exploded view, I'm seeing that there is an O-ring between the bottom of the pump housing and the pivot point - is this likely to be the issue?

    TIA
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    You're likely on the right path, blown O-ring on the base lug. Not a bad fix as long as the mounting bolts will come out and the threads in the housing are in good shape. They can get pretty bad as they age.
     
  3. jjorgensen52

    jjorgensen52 Junior Member
    from NH
    Messages: 3

    I replaced the O-ring and the base lug (old one was seized to the pivot pin, had to cut it to remove). The threads on one of the bolt holes are not in great shape, as you describe. Can they be successfully rethreaded or helicoiled? Don't really want to replace the whole housing.
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Heli-coil will work or better yet a Time-Sert insert if you know someone with a kit. Properly done either one will be stronger than the original threads. I'll often just go ahead and do them both while I'm there. Saves from having to do the other one the next time.
     
  5. jjorgensen52

    jjorgensen52 Junior Member
    from NH
    Messages: 3

    Did the helicoil this evening, bottom lug is no longer leaking. Of course, I've now identified a second leak in the driver's angle hose (which is only 4 months old???). I can't win :dizzy:

    Anybody have a 7'6" MM2 they want to part with cheap :laughing: