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No lift pressure.

Discussion in 'Western Plows Discussion' started by engineeradam, Sep 17, 2012.

  1. engineeradam

    engineeradam Junior Member
    Messages: 2

    i have a 87 gmc 4x4 with a old western cable operated exterior plow pump with a brand new motor on it that i wanted to get ready before the winter. Problem is there is no lift pressure. It wont even lift my skinny a$$. I took the pump out and cleaned the screen and filed the reservoir. I was wondering if someone could tell me how to test the pressure. Ive also heard of a pressure relief valve?

    Any help is much appreciated.
    Thanks Adam.
     
  2. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    Have you removed the cover from the raise lever to see if the cable is closing the valve all the way? It could be the gate is not closing all the way. The other option could be an out of adjustment lift valve. If that is the case read the manual on the western site VERY carefully and be sure you understand it. it is kind of tricky.
     
  3. nealybird

    nealybird Senior Member
    Messages: 717

    yes there would be a relief adjustment on the pump itself that you could try cranking up a little. check the mechanics guide for that. and you can check pressure with a pressure gauge coupled into a coupler on an angle cylinder. see the mechanics guide for detailed instructions.
     
  4. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    On the old cable controls I think you'll find that doesn't work. If the valving is adjusted correctly the angle pressures should be balanced at 450 psi while lift pressure should be north of 1750lbs.

    If you want to experiment before you play with pressure reliefs try adjusting the lift valve.

    You do this by slightly loosing the nut (15/16) on the rear of the pump while holding the adjuster still with a hex wrench. DON"T LOOSEN MORE THEN 1/16 TURN or the o-ring will bulge, loosen it just enough for the adjuster to move. Turn the adjuster in no more then 1/8 turn. Try raising (leave the plow attached or you may have a female dog getting it down,) if it raises see how fast it drops. If it drops too fast or doesn't raise repeat, never turn the adjuster more then 1/8 turn at a time. Get the adjustment to far out of wack you'll be having angle problems next.
     
  5. engineeradam

    engineeradam Junior Member
    Messages: 2

    Thanks alot guys. Ill read and adjust in the near future. Just busy with school. And ill let you know my progress. Thanks again
     
  6. Chiputz

    Chiputz Senior Member
    Messages: 165

    It may sound too simple but, are you sure the o ring under the pump inside the reservoir didn't move on you when you were installing the pump? Pull the motor back off and put a drill on the pump shaft, you'll see the fluid gurgling around inside the reservoir if it's leaking.
     
  7. Chiputz

    Chiputz Senior Member
    Messages: 165

    If it worked before you serviced it I should have said.
     
  8. nealybird

    nealybird Senior Member
    Messages: 717

    checking the pressure on an angle cylinder doesn't work? sure it does. see pg 4-2 of the long mechanics guide.

    http://library.westernplows.com/westernplows/pdf/62880.pdf
     
  9. nealybird

    nealybird Senior Member
    Messages: 717

    hmmm. you're saying to try turning the lift valve (on the front of the power unit) in, which may be correct, but you're describing the check valve (on the back of the power unit), which would be incorrect. you turn that in if the blade won't lower or lowers too fast.
     
  10. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    If you turn it out to far the plow will not lift. The check valve and the lift valve work together. While the lift valve may need to be adjusted, the check valve in the rear can be lose enough or the spring tired enough it no longer seals at the shuttle. Tightening it just a little has I suggested often will correct that. We found this to be the first thing to check as it's easily corrected if wrong and rarely effects the angle functions if over adjusted and often moves easier then the lift valve.

    Adjusting the lift valve in the front can be a bear. The older metal ones liked to seize and the later plastic ones would swell and then strip the hex. All in all I prefer the plastic ones as they are easier/cheaper to remove and replace. I have a new lift valve on the shelf if you need on and cannot find one easily.

    Page seven this manual explains and has pictures.
    http://library.westernplows.com/westernplows/pdf/13497_020088.pdf

    Of course I admit we stopped installing them in 94 and haven't had many in the shop in the last few years.
     
  11. nealybird

    nealybird Senior Member
    Messages: 717

    I'm not sure if that's true or not, but engineeradam didn't mention that he had been messing with that. he just wanted to know how to check the pump pressure and if there was a relief.

    the shuttle seats against the shuttle by the cam moving it there, not from the spring in the check valve. the spring in the check valve that seats that ball is what keeps the plow from drifting down.

    this is true, but I wasn't suggesting he try to adjust it, I was merely pointing out that you said adjust the lift valve but then described the adjustment for the check valve.

    yes it does. and it says to turn the lift valve in if it won't raise and turn the check valve in if it won't lower. but again, he didn't sound like any of these had been messed with, and just wanted to know how to check the pump pressure.
     
  12. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    Not wanting to argue just trying to share my experance working on these units and give him a quick trick that has worked for me and can be done easily without taking the pump apart or buying tools.

    You've never had a unit with a failing/weak check valve allowing the blade to drop?
     
  13. nealybird

    nealybird Senior Member
    Messages: 717

    yes, I didn't want to sound argumentative either, and all I'm doing is trying to help people also. I just figured I needed to answer the points you brought up. no worries.