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Unimount leaking at bolt hole

Discussion in 'Western Plows Discussion' started by FourDiamond, Jan 31, 2015.

  1. FourDiamond

    FourDiamond Senior Member
    Messages: 129

    We have a 15 year old Western MVP Flostat 66587 that has developed a leak at a bolt that runs from the fluid reservoir to the pump motor. The bolt also seems to hold a guard in place in front of the lift cylinder. The leak occurs even with the plow resting on the ground with only minimal hydraulic pressure in the system. I think there must be an o-ring or similar gasket in both ends. Any ideas on the set-up. We're getting snow tomorrow so it won't get changed until Tuesday, but I would like to have an idea of the set-up before I turn a wrench.
    Thanks in advance for any help.
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,969

    Ok, how.about a pic.....otherwise you got me
     
  3. FourDiamond

    FourDiamond Senior Member
    Messages: 129

    Dieselss,

    As I was typing this I thought the same thing. Unfortunately, the truck is onsite so pictures are out until Tuesday or Wednesday.
     
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,969

    Unimount I'm assuming?
     
  5. FourDiamond

    FourDiamond Senior Member
    Messages: 129

    Yes it is.
     
  6. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    There are two long bolts that hold your motor on, they run the full length of the motor into the valve body. There is nothing that goes from the motor to the reservoir....

    Perhaps you are talking about the two bolts that secure the lift cylinder bracket to the valve body? These two bolts just run through the valve body but they don't come in contact with any fluid channels so there are no seals or o-rings. You can take those bolts right out and no fluid will come out even when the pump pressures up.

    I think you need to clean off the leaking fluid and then put it through the motions and look again for where the fluid is actually coming from. I suspect the fluid is running down from a higher location and just appears to be coming from that bolt. It could be leaking past the pump motor shaft seal (item 13) and then leaking out where the motor contacts the valve body or another likely thing to look at is the reservoir o-ring (item 50), if the fluid appears to be coming from the reservoir side. See this link on page three for those two items. http://library.westernplows.com/pdfs/63652_010504.pdf
    Remember that the vent cap holds 5psi in the reservoir at all times (unless you open the res and release it) so even when the pump is not in use it will force fluid out until that pressure is gone. Like a submarine, higher pressure inside keeps air leaking out and prevents water from coming in. That 5 psi keeps the fluid moisture free.
     
  7. FourDiamond

    FourDiamond Senior Member
    Messages: 129

    After looking at the diagram on page 3. The fluid is coming from the reservoir side of the unit. Going from memory(which is getting worse as I age) the leak may be coming from bolt 14, which based upon the diagram means the o-ring #50 could be bad. The 5 psi held in the reservoir would explain the continuous leak. I'm go to the site later today, and will post pics. Thanks.
     
  8. FourDiamond

    FourDiamond Senior Member
    Messages: 129

    Here are a few pics for the problem. The unit continues to have a steady drip of fluid. Sorry for the quality

    western flo stat 001.jpg

    western flo stat 002.jpg