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western unimount 7.5 straight blade

Discussion in 'Western Plows Discussion' started by jgtools, Oct 15, 2014.

  1. jgtools

    jgtools Member
    Messages: 33

    what causes a slow lift.? right and left side movement is quick, but up is much slower. thanks jim
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,935

    Could be bad motor, bad pump. Generally pump so I'd say preform a psi test and Ck the numbers.
     
  3. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Pressure test is great if you have a gauge, you should get 1750 psi if things are good. There is a pressure relief valve that could have a broken spring or perhaps someone messed with it? If the motor doesn't have the juice to turn the pump you would have reduced pressure too. Consider things that would make it work harder to lift like the lift ram packing nut being too tight or the quill valve is turned in too far. This plow has no quill bypass so fluid goes through a restriction both up and down, (quill valve controls drop speed) newer models only pass through quill on the down stroke. There is an o-ring under the pump inside the reservoir, if that seal is missing or broken pressure leaks away before the valve body. Check out the mechanic's guide page 46 for pressure test procedure.
    http://library.westernplows.com/westernplows/pdffiles/21936_121704.pdf
    Assuming this is a uni with flowstat hydro unit, I don't think they made any uni flowstats except Vs
     
  4. jgtools

    jgtools Member
    Messages: 33

    thanks, where would I hook up the psi gauge?. thanks again
     
  5. jgtools

    jgtools Member
    Messages: 33

    thanks, I will check things out this weekend, I let you know what I all find. thanks for the links
     
  6. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,935

    Make sure you get a gauge capable of 3000 psi.
     
  7. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The link I sent shows where to connect it. Actually you will be testing at the base of the lift ram. It's a small pipe threaded hex head plug. There is another port that measures directly from the output of the pump but I can't remember off the top of my head which one.
     
  8. jgtools

    jgtools Member
    Messages: 33

    I have a quick connect psi gauge that goes to 4000lb. I would need to find the right quick connect adapter for the test port, also if I see for the standard / pro plows the psi should be around 1750 at full lift. I assume my older unimount 7.5 straight blade plow would fall into this category (standard or pro plow) thanks again.
     
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,935

    1/4 pipe I believe. Yes yours should be about there in the psi range
     
  10. jgtools

    jgtools Member
    Messages: 33

    1410 was the best I got on the psi test at full lift. pump is quiet, but really slow lifting.. ? not sure what to do next. pump overhaul, or tear into it , clean everything out, and check o-ring (s) thanks,JG
     
  11. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    1410 is pretty good. If that was measured at the base of the lift ram. Was that while lifting or max pressure after hitting end of ram travel? How do things move with the plow unhooked? If it still moves slow then perhaps an oil path is restricted with debree. Try blowing out the fluid paths with compressed air. Also try turning back the quill screw
     
    Last edited: Oct 19, 2014
  12. xjoedirt55x

    xjoedirt55x Senior Member
    Messages: 104

    Just throwing other possible ideas out there... but if the pressure he is getting at the base of the ram is decent, could that mean there is water, or even air trapped in the ram some how that doesn't quite drain off all the way when pressure is relieved?

    Also, I would not mind finding myself a pressure gauge for hydraulic lines.... is that something I need to look for a specific brand setup, or something I can go to a rural kind or tractor supply and get a standard pressure gauge with a line and the correct fitting? Input would be great as I would like to have all tools needed to troubleshoot my equipment if needed.
     
  13. jgtools

    jgtools Member
    Messages: 33

    1410 was observed at top of lift max. The quill screw is backed off as far as possible, infact the snow plow shakes the ground when I trip it down. . The thing is , if I turn the quill screw in , seems to be no effect on lift speed or drop speed...another clue for me to trouble shoot, I guess ,lol.
     
    Last edited: Oct 20, 2014
  14. jgtools

    jgtools Member
    Messages: 33

    I got my hyd psi tester at northern hydraulics , few years back,first time using it.
     
  15. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Water will have no effect on lift speed unless it's freezing or causing corrosion.
    Since drop speed is good and pressure is resonable I would look for a restriction in the inlet oil path. Outlet path is not restricted so that narrows it down. I would check that o ring under the pump too.
    As far as gauges go there are many kits available. I made mine out of scrounged gauges an adapters & fitting I collected over years. Buy them as u need them.
     
  16. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,935

    I'll say this. If you pump adjustment screw is all the way out and your still about 400 psi shy, I'm thinking pump. If there were restrictions your psi would spike.
     
  17. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Yes pump is a strong possibility but clearing the fluid galleries and checking the o-ring is free. A pump is the next step I would recommend after verifying those two factors. You have to take the pump out to check those so check the gears for wear at the same time. May very well be that the pump gears are so worn that it can just barely make 1410 psi but the displacement volume is very low because the fluid is leaking past the gears. On bigger equipment we would do a flow test but that is not an option here.
     
  18. jgtools

    jgtools Member
    Messages: 33

    Thanks you all, very helpful . I appreciat all the knowledge given on this issue. I willget time again, possibly Friday to remove pump and inspect. Question...what is the cost to replace the pump, if it needs replacing? Thanks.Jim
     
  19. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The last one I bought cost over $300 here in Canada but I am sure they are less in the US.
     
  20. jgtools

    jgtools Member
    Messages: 33

    Cool,thanks. I will start to call around, and check availability and prices. Still warm here in Minnesota' but have a feeling a change in weather will happen soon. Need to have this old plow ready !