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MM2 insta-act pump will not keep straight

Discussion in 'Fisher Engineering Discussion' started by shooter56, Feb 24, 2015.

  1. shooter56

    shooter56 Member
    from ct
    Messages: 57

    I have a fisher mm2 with a insta-act pump. It works up down side to side no problem. But when I am pushing the plow will swing to one side, right or left does not matter. I have been reading about the crossover valves on the pump. They could be the cause.

    So I pulled the pump off and thought maybe I could adjust them, yea right. Those suckers were frozen solid in the body, even the pump pressure valve was frozen. I tried a big screwdriver, a bolt ground to a screwdriver tip, a impact with a screwdriver tip on it, no sir they would not move. So I tried heat, my plumbers torch first, not enough heat, so I used a ox-acy torch and put it down inside the hole and heated and it came loose, and after spraying a lot of deep creep in the hole and working them a while I got them all loose and out.

    Now should I go buy all 3 valve assembly's or use the reseating method and just put them back in? Could any of the electrical solenoids have something to do with the blade moving to the side?

    thanks pat
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,983

    Since you have them out, I'd go get new ones.
    No the coils have nothing to do with it.
     
  3. shooter56

    shooter56 Member
    from ct
    Messages: 57

    Thanks dieselss for the quick reply!

    There are 2 poppet valves in the valve body. What is the function of those? Any ideas? I have been reading by just cant seem to figure out what they do.
     
  4. TJS

    TJS PlowSite.com Addict
    Messages: 1,344

    Be careful heating the manifold to get the crossovers out. Hopefully you removed all the O ring stuff elsewhere in the manifold first. I made this quick tool just for this purpose.
    [​IMG]
     
  5. shooter56

    shooter56 Member
    from ct
    Messages: 57

    Saw that, pretty sharp. I did not heat it so much that it affected the o rings. I was very careful to direct the heat to the valve. I used the small Victor tip to get down inside the hole.
     
  6. shooter56

    shooter56 Member
    from ct
    Messages: 57

    Put it all back together today, changed the fluid and ended up putting both crossover valves and the pump pressure relief valve in. I adjusted the pump relief 2-1/4 turns out and the crossover valves 1-1/4 out seems to work ok, up down right left fine I will see the next storm.

    I do not have a gauge to check the pressure, should I get it checked? or just leave it.
     
  7. shooter56

    shooter56 Member
    from ct
    Messages: 57

    Thought I would clean up the yard today, the plow still moves when I push up on it, not as bad but still doing it. It did not do this last year, could the one of the electric solenoid valves leaking? I guess I should get a pressure gauge to check the pressure.
     
  8. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,691

    Only other thing I can suggest to check is the poppet check valve. If it is stuck open could allow blade to drift. But I would still double check the crossovers and reseat them.
     
  9. shooter56

    shooter56 Member
    from ct
    Messages: 57

    I put the 2 crossover valves New and the pressure relief valve New. I would have to reseat the New ones also?
    So the poppet valves will hold the plow from going to one side?
     
  10. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,691

    Been awhile but think if poppet is stuck open the blade will be able to drift to the left. As for seating the reliefs, it can't hurt. Also are you sure you got the correct reliefs, think there are two different styles.
     
  11. shooter56

    shooter56 Member
    from ct
    Messages: 57

    The valves are the same, thanks
     
    Last edited: Feb 26, 2015
  12. shooter56

    shooter56 Member
    from ct
    Messages: 57

    I think I will pull the assy off the truck and pull it all down, clean the entire thing inside and out including the solenoids. The poppet valves are just a bit over $30.00 so I will get new ones and new o rings for the rest of it. My motor is a tad noisy so while it is apart I will put a new one on I can get the old one rebuilt. I ordered a pressure gauge today so I can check it the way fisher suggests.

    I have 32 accounts and I just want it to work right.
     
    Last edited: Feb 26, 2015
  13. shooter56

    shooter56 Member
    from ct
    Messages: 57

    Got the pressure gauge today and put it on the lift cylinder and the pressure was just a bit over 1000psi so I was able to turn it up to 1750, no pump motor yet, due to come on Thursday the old one is noisy but still working, I will see how the plow works later cause we are getting a sloppy mix tonight.
     
  14. shooter56

    shooter56 Member
    from ct
    Messages: 57

    I went out and plowed the last 2 storms, it raises great, but the angle seem to need to hold better. I need more info on the left and right cylinder pressure. I read 4000 psi is that right?