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Western Unimount no low pressure

Discussion in 'Western Plows Discussion' started by Blizzardbusters, Jan 20, 2013.

  1. Blizzardbusters

    Blizzardbusters Junior Member
    Messages: 8

    So I was brought a plow to work on by a customer he said that his plunger arm was leaking bad because of pits in the chrome so he wanted me to put a new plunger and seal kit/ packing. (This was in the middle of the last storm) when he dropped it off he told me that it would not lift any more because it leaked all the fluid out. So I did the replacement of the plunger arm and packing and serviced the plow. When I went to lift it up after I was done I hit the control and the motor turned but no pump noise and it lifted up till all the slack came out of the chain then just stopped with no pump noise/whine whatsoever. So I put a pressure gauge on it and it reads 600 psi at dead head when plunger stops. So I pulled the motor off and took off the pump expecting to find it trashed because of low or no fluid. Looked fine no foreign metal o ring still on bottom. Took it all apart cleaned it cleaned the pressure relief valve/ball all looked great put it all back together still no no than 600 psi western tech says 1750psi at any point. So to eliminate things swapped motor and jumped from seperate battery to eliminate truck still does the same all functions work correctly just not enough pressure could it still be a coil or valve not opening all the way like s-1 ??????? The packing nut is not to tight either I'm at my wits end with this thing any thoughts?
     
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    This sounds like an old Isarmatic unit with the lift ram intigrated into the pump housing. 600 lbs is very low, sounds like the pressure is bleeding away. Maybe the o-ring under the pump is damaged or missing. If you had the pump out of the housing then you may have overlooked that in which case the fluid will leak away before it gets to the valve block. Check that out and let us know for sure if I guessed right on the type of plow. Then if you still have problems we can help you with more detailed assistance.
     
  3. Blizzardbusters

    Blizzardbusters Junior Member
    Messages: 8

    Yes you are right on the type of plow. I did check the oring on the bottom of the pump and it looks great no slits no damage.
     
  4. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Ok so the O-ring is good now you have to focus on the valve block. There is a plug in the front of the valve block that will allow you to test the pressure directly at the output of the pump. Most people test the pressure at the base of the lift ram, is that what you did to get 600 lbs? You need to verify if the pump is producing no pressure or if it is being bled off by some valve problem. Connect the gauge to the plug on the block and see what the pressure is there when you use a jumper to activate the motor without using the controller (so no valves open) If the pressure is low there I would be looking at the relief valve and then the pump. If the pressure is hight then look at the valves. Do you have the manual? The link to the Western web page is not working but it will probably start working in time...
    http://library.westernplows.com/westernplows/pdf/21936_121704.pdf
     
  5. Blizzardbusters

    Blizzardbusters Junior Member
    Messages: 8

    ok i will check this and yes i do have a manual i will let you know
     
  6. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    It might be possible you just have too much "air" in the system!