1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

Uni Mount Problems

Discussion in 'Western Plows Discussion' started by linckeil, May 4, 2009.

  1. linckeil

    linckeil PlowSite.com Addict
    from CT
    Messages: 1,265

    So I just picked up a 1996 F350 with a Uni-mount on it. The plow wasn’t working when I got it, so I’m going through it now. I have zero experience with the Uni-mount but know the conventional set-up well.

    I put in a new solenoid so now I have power where I should and the pump runs. But there are still problems. When angling left, the plow goes right. When raising, the motor hums, but the blade doesn’t go up. I downloaded the mechanics manual online and ran through it. .

    So based on my symptoms, it appears there is a problem with the S3 (4-way) coil/valve.
    The manual says to check for magnetic pull at the coil. S1 & S2 have magnetic pull when running the corresponding function, but there is no magnetic pull at S3 when angling left or raising (or at any function for that matter). The manual says to check the resistance at the coil. It should have 6.7 ohms of resistance. All 3 of the coils have about 7.1 ohms – including S3.

    So what is my problem? The resistance is where it should be, but there is no magnetic pull. Is the S3 coil shot? Or is the S3 solenoid cartridge valve bad? I have yet to remove either from the unit. Does it sound like just the valve is stuck and needs a cleaning?

    Thanks
     
  2. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Check for power on the wire at the coil along with ground on the black orange at the coil. Ground should be constant, power will be when function selected.
     
  3. linckeil

    linckeil PlowSite.com Addict
    from CT
    Messages: 1,265

    yes, power is there, ground is good. i think i have it narrowed down to a bad coil or a bad valve - or maybe both... i want to get the correct part to fix it.

    so good resistance at S3 coil, but no magnetic pull.... what do i need to replace?
     
  4. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Take the coil and valve right off the plow. Check the valve for movement by placing a small screw driver in the end of the valve and giving it a push. Does it move? Movement will be very slight and will have to look closely to see it. Check for debris in the valve that may be causing it to stick, sometimes a good tap of the end of the valve on a wood block will knock the debris lose. Check for movement again. If not then put the valve and coil together off the truck, get 2 jumper wires and using the battery in the truck hook the coil up to the battery. When you make the last connection you should hear the valve click and see it move. If no movement try another coil to rule out the coil. Still no movement, then more than likley the valve is bad.
     
  5. linckeil

    linckeil PlowSite.com Addict
    from CT
    Messages: 1,265

    sounds like a plan. so the coils are the same can be moved from one valve to the other? hopefully after work tonight i'll have a chance to check it out. i'll keep you posted. thanks for the input.
     
  6. linckeil

    linckeil PlowSite.com Addict
    from CT
    Messages: 1,265

    so i removed the valve and coil. valve looked clean, i pushed on it and there was movement. i put the coil on and hooked it to the battery and the valve moved. so i installed it back on the pump and all worked fine for about 30 seconds, then it started behaving like it was before. i messed with the grill connection and it started working again. so the problem all along was just a bad plug connection!!! but thats ok, this experience gave me a much better understanding of how the unimount setup works.

    i'm gonna hit the plug connections with some brake parts cleaner and then apply some fresh dielectirc grease. hopefully that cures the connection problem. if not then i guess i'm gonna need to splice in some new plugs...