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Boss pow will not lift

Discussion in 'Boss Plows Discussion' started by Lowes, Jan 28, 2010.

  1. Lowes

    Lowes Member
    from Mo
    Messages: 70

    I have been having a world of trouble with the 8.6 straight blade.
    I have just replaced the motor. My motor was bad, the brushes were gone.
    With the new motor installed I have left and right movement but no lift.
    It lifts just enough to take make the truck sag a little.
    I have checked this chart:
    http://service.bossplow.com/Documents/rt3_straight_blade_troubleshooting_guide.pdf
    I believe this may be where my problem may be. As I have check all other Items under the list

    [I]If pressure is less than
    2500 psi (at end of lift).
    Motor brushes may be
    defective, pump pressure
    relief valve may be
    contaminated, damaged, or
    set less than 2500 psi,
    pump may be w
    [/I]

    Can I have left and right movement with out any real lift?
    I how do I check/adust the pump pressure relief valve?
    I have removed it and cleaned it with carb/choke cleaner.
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Yes you can have angle functions but no raise since it takes very little motor power or pump PSI to angle. 700 PSI will easily angle the blade but won't come close to raising it.

    If it lifted fine before you fooled with the motor then I'd say you have a motor problem (saw your motor thread from the other day). What year is this plow btw? Serial number?

    And now that you also fooled with the pressure relief you'll need to reset the relief. To do that you need to get a gauge on it to set it correctly, otherwise you're just guessing on the proper PSI.
     
  3. Lowes

    Lowes Member
    from Mo
    Messages: 70

    The plow I think is a 2004 as the valve manifold has Hf25791-04
    I had the old motor sent off to a core rebuilder. The motors spins freely.
    How do I reset the pressure relief valve? I just unscrewed it from the valve body.
    I can't say for sure if it did left freely as the motor was weak.
    At this point I'm ready to scrap the plow and go back to Western.
    I chose years ago to go to Boss as I liked the quick connect system vs the Unimount.
    Now that I have friends with the ultra mount I see little advantage.
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If you had the pump relief valve apart in the pump manifold, then as I stated you need to get a pressure gauge tee'd into a lift or angle hose and check/set the pump PSI accordingly. Needs set to 2300 PSI. Or was it an angle relief valve from the valve manifold that you disturbed? Makes a big difference..

    Did you ditch the cheapy eBay motor and get the right one on there? Pointless to complain about a 6 year old plow that's being repaired with cheap parts as cheap parts are nothing but problems. Would have also been a good time to upgrade to the double stud Iskra motor too.
     
  5. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

  6. Lowes

    Lowes Member
    from Mo
    Messages: 70

    I borrowed a hydro tester. I connected it to the middle elbow then zip tied it to the mast so I could see it from the truck cab. Putting this inplace instead of the lift cylinder. The needle would go up just a little higher than picture when the raise button pushed. It would just reach 1000 PSI. It would hold to take the camera shot. Push down on the controller and it would go down under 100. The dealer is a 1 1/2 away, the snow has come and gone. The Boss let me down. Next week it will make trip to the dealer. Over the phone I talked to Cost Cutter sales. They are a little further away but over the phone much better to deal with.

    hydro gauge.jpg
     
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Turn the pressure relief up and see if the pressure comes up with it.
     
  8. Evanbrendel

    Evanbrendel Senior Member
    Messages: 181

    just curious where in missouri are you located?
     
  9. Lowes

    Lowes Member
    from Mo
    Messages: 70

    I was told by the dealer not to mess with this also.
    How do you even adjust it?
     
  10. Lowes

    Lowes Member
    from Mo
    Messages: 70

    Our business is located in Cuba Mo.
    I live in Gerald and here I get the fun task of working on all the equipment.
     
  11. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    You stated in one of your previous posts that you disassembled and cleaned the relief? :confused:
     
  12. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    :popcorn:.
     
  13. Lowes

    Lowes Member
    from Mo
    Messages: 70

    Yes, unscrewed it looked at it screwed it back in. No change in the operation of the plow.
     
  14. Lowes

    Lowes Member
    from Mo
    Messages: 70

    Thanks for you post replys. I'm sure by giving the above comments your post count is higher than ever. I'm glad you can sit back and eat popcorn while others are out working.
     
  15. doo-man

    doo-man Senior Member
    Messages: 387

    To adjust it I think you need an allen wrench and a box end to hold the valve body, I do not know how I just watched while the local shop worked on mine ! I am sure B&B will chime in !!!
     
  16. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    It sounds like you may have the pump pressure relief confused with the angle relief valve. When you removed this valve, where exactly did you remove it from? From the block between the reservoir and the motor....or from the manifold block that all the electric valves are in?
     
  17. Lowes

    Lowes Member
    from Mo
    Messages: 70

    I removed the valve on the manifold block just under the two coils for left/right
    I removed the coil but did not take the allen head wrench to this. I thought this might be how you would adjust it, but not sure. The main thing I was looking for was any dirt or containment in the manifold body or the screen at the end of the valve.
    Boss pat number
    HYD07027
    VALVE,RELIEF CART. FOR HYD7019,7090,7091
     
  18. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    As I suspected. Thats the angle relief, has nothing to do with pump pressure. The pump pressure relief is on the front of the pump manifold under the large hex nut. Remove the hex nut and give the screw behind it one half turn and check the pressure on the gauge again. If it doesn't come up then you have other issues, like the motor is weak which is what I foresee.


    Be sure to turn the relief back down once you're done with the test. :nono:
     
  19. Lowes

    Lowes Member
    from Mo
    Messages: 70

    The dealer installed a new pump/motor.
    I understand the pump was just weak.