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MM2 pump motor works intermittently

Discussion in 'Fisher Engineering Discussion' started by PewterZ, Jan 16, 2013.

  1. PewterZ

    PewterZ Junior Member
    from Mass.
    Messages: 6

    A friend of mine has an 04 f350 gasser with a MM2. First off, this plow has had a tough life. He used to plow for the state and hes not easy on his truck or the plow. its had countless cutting edges broken, new trip edge last year. Where the center pin goes through the top of the blade, its all stretched open. Its in rough shape compared to most MM2's ive seen, but anyways. A few seasons ago just before the first storm he found that his pump motor was siezed. Put a new one on (aftermarket), worked great until halfway through first storm. Ended up having water intrusion inside the pump motor. Replaced it again, RTV'd every seam, bolt head and any possible place for water to enter. That seemed to take care of the water intrusion issue.

    Just a couple weeks ago during the first storm this season, he had the plow quit on him again. This time, when trying to raise the plow, the motor was drawing so much current that it apparently stalled the truck and it had to be jumped. Thinking it was another bad motor, it was replaced again with the same brand of aftermarket motor. After that it worked great again.

    It did the same thing this morning trying to plow this storm. Worked for about 45 mins he said, then it killed the truck trying to raise the blade. Jumped the truck, worked great again for an hour, then did it again. He isn't overworking the motor by any means, says he moves the blade maybe half a dozen times in an hour, hes just plowing back roads nowadays, no longer plows for the state, he doesn't do any lots or driveways.

    I'm thinking maybe bad solenoid, or maybe the pump itself is getting hung up intermittently and the motor cant turn it? A solenoid is cheap enough to try. But i figured id see what you guys had to say. Maybe one of you has seen this before. Thanks in advance.
  2. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,039

    How many times do you have to bang your head against a wall, until you figure out it's not the walls fault that it hurts...it's yours. In short, get a OEM motor and stop wasting time. While it's apart, drain it, remove the coils and valves and give it a thorough cleaning. Put it all back together, fill it with good ole Fisher blue, and seal it up...less headaches, more money in your pocket. Happy plowing!
  3. kimber750

    kimber750 PlowSite Veteran
    Messages: 4,678

    Agree 100% with RepoMan, but would like to add... check all connections, especially the plug for the motor. Make sure these are clean. Corrosion can be a killer.
  4. ducaticorse

    ducaticorse PlowSite.com Addict
    from we
    Messages: 1,426

    Sounds like a bad ground or a bad connection. If you are shorting out the truck like that, you are beating the F out of your alternator too. The aftermarket motors work, and getting a FISHER motor probably wont solve your issue. The only other thing I that it may be is a pump about to fail. If the pump isn't working to capacity, it will draw more power to do the same amount of work.

    Also, purge the entire system. Pop the lines off the rams and clear them out. I run ATF in all my plows, I'm in MA, and it works fine for me, and costs half as much as blue. Some guys in severely cold areas claim ATF is a little less viscous at sub zero temps, so keep that in mind too.
    Last edited: Jan 18, 2013
  5. leigh

    leigh 2000 Club Member
    from CT
    Messages: 2,342

    This isn't your problem but will be,don't seal up where the motor meets the pump.it needs to be left the way it comes so it can drain.I run a aftermarket motor and its fine.Might want to check the quill adjustment. And to repeat,clean all electrical connections and grounds!