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Plow slowly drops-doesn't stay up?

Discussion in 'Commercial Snow Removal' started by bikeluver43, Jan 19, 2005.

  1. bikeluver43

    bikeluver43 Member
    from Mass
    Messages: 84

    Hey guys, I just purchased a used Fisher minute mount 1, 7 1/2' plow setup for my F150. I put the plow on and everything works-except when I have the plow in the up position, it will slowly over time droop down. It will happen slowly while I'm driving and I have to readjust it to the full up position about every 5-10 minutes. The hydraulic setup is the older electric motor/pump with hoses to a cable operated valve, then the hoses hookup outside the truck to the plow. I was thinking it may be a valve but am not sure. Any idea's?

    Also-I've seen a ton of meyer E47's and controls on ebay for good prices, and am considering buying an E47 pump, and using the wiring/controls on my fisher setup= Would this work/bolt up? I'd like to get rid of the older valve setup I'm running now that is inside the engine compartment. Thanks.
  2. Mark Witcher

    Mark Witcher Senior Member
    Messages: 605

    Plow leaking down is caused by things such as,leaking valve, check valve, or cylinder packing.
  3. bikeluver43

    bikeluver43 Member
    from Mass
    Messages: 84

    Is there one that usually goes first before the others? I'd hate to go replacing the things that aren't broke.
  4. mdb landscaping

    mdb landscaping Senior Member
    Messages: 823

    im sorry to say, but your plow is totaled. time to get rid of it. :D
  5. Mark Witcher

    Mark Witcher Senior Member
    Messages: 605

    Sometimes you are money ahead to just take it to a plow repair shop instead of just guessing .
  6. bolensdriver

    bolensdriver Senior Member
    Messages: 603

    About every plow I know slowly goes down. Even the town's plows.
  7. PetalsandPines

    PetalsandPines Senior Member
    Messages: 260

    Probably the packing cup

    Replaced mine in November, stayed up for a month and is now leaking down again...The heck with it....I'll just keep propping it up every 5 minutes. Done sinking money into S&%^ Meyer Plow.....Love my Blizzard though!!!
  8. Bolts Indus.

    Bolts Indus. PlowSite.com Addict
    Messages: 1,176

    Blizzards don't creep down.
  9. Mower For Less

    Mower For Less Senior Member
    Messages: 108

    Blizzards dont use a cylinder packing that can wear? Please explain why Blizzards are immune to wear and creep. My Meyer creeped when I bought it. I rebulit the pump to solve the problem. Now I have driven with it up for 1 hour, and no creep in that hour.

  10. bikeluver43

    bikeluver43 Member
    from Mass
    Messages: 84

    I guess I'll just live with it for the season and have a shop check it out later or just upgrade to the newer style pumps.
  11. justme-

    justme- 2000 Club Member
    Messages: 2,138

    Bikeluvr, this isa very common problem with older plows, the most likly cause is the valves are worn. the valves take a beating when an operator drives from plow site to plow site without useing the carry chain. The added weight constantly on the lift circuit and the bouncing over road depressions litrely hammers the circuit. My chevy has the same problem.
    If the cylinder was leaking down due to the internals being worn (not packing) it would result in oil being discharged from the vent when you raise the plow. The lift cylinder is a vented single action meaning oil only enters one side and can only act in one direction (to lift) the weight of the blade retracts the cylinder. In order to function the reactive portion of the cylinder (on the other side of the piston seal) must be vented lest on lift there would be pressure built up and blow the cylinder seals out and vacuum lock on float. If oil gets past the seal into the vented side it will be forced out the vent so you will see oil on the cylinder.
    If the packing was leaking the plow would leak down faster than that AND there would be obvious leaking on the lift cylinder (the packing is at the top of the cylinder body).

    New valve bodies can be had for less than $100, try northerntool.com.

    Also, if you have the room under hood stay with what you have- I have the later version MM1 with the "unipack" all on the lift frame and I hate it. I have no under hood room to install anything so I am stuck with it. The bottom mount tends to loosen and leak, the body is prone to stripping of threads...

    If all you want to do is replace the hydraulic supply I am sure you could modify any other manufacturer's pump/relay/valve unit to work- the question is why. I think there's a reason why Meyer parts (older parts mind you) are cheap and plentiful- there must be a market for them (broken plows).
  12. bikeluver43

    bikeluver43 Member
    from Mass
    Messages: 84

    Thank you for such a great response. I was thinking it was the valve because the piston itself has no leaks and is completely dry when lifted. Its a slow drop and your right, I drive over very bumpy roads up here in New Hampshire, so there is a lot of bouncing by the plow. I don't think my plow has a travel chain to take the stress off the piston, although I wish it did. The reason I'd like to go to the "on the plow" unit is because space is tight under my hood. I was just barely able to mount the pump and valve underneath it, while repositioning other parts of my truck. I just feel it'd be easier to hook up two electrical connections rather than frozen hydraulic hoses also.
  13. justme-

    justme- 2000 Club Member
    Messages: 2,138

    Makes sense. Look for later MM2 componants- better system and mount on the lift frame. FWIW the electrical connections are as much troublesome as the hydraulics ones- the pins need to be kept clean and greased, the control plug tends to work loose (Fisher has a metal clip that hooks in the boot for the plug to hold it in), the wiring harness needs to be redone (new plug put on) from time to time (I replaced my 2 seasons ago) from broken wires behind the plug and stiffening of the rubber. Each has it's problems.

    On the lift frame there should still be a "hook" on the drivers side for the carry chain- just run a piece from the a frame (near the lift chains mounting point) and there you go. Some of the MM plows had a single piece of chain running from a frame to lift frame point through a d ring (instead of a hook), back down to the aframe and then th tail was the carry chain (mine is this way).