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Pressure relief valve

Discussion in 'Boss Plows Discussion' started by maverjohn, Jul 6, 2011.

  1. maverjohn

    maverjohn Senior Member
    Messages: 902

    My left wing on my RT1 V plow will not hold, I read were B@B helped Mountain Mog with the same problem and applied it to my plow, New o-rings, PSI is 2400, in that line and still no luck,
    The numbers on the side of my relief valve are not readable and I have no manual for the plow.
    So my quistion is this a HYD1639 relief valve?
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    As long as it isn't a very very early manifold you can use the current HYD01639 relief as a replacement.

    Have you disassembled/cleaned and/or adjusted the relief yet? They don't always need replaced to fix the issue.
     
  3. maverjohn

    maverjohn Senior Member
    Messages: 902

    Thanks B&B, I will try taking it all apart and cleaning it first.To get to 2400psi after I replaced the o-rings I turned the adjusting nut inside the valve, but it bottomed out after a half turn.
    I was told the plow is a 1993 model, put on a 1994 chev as a back up plow for a small school in our district.
    this plow has worked great for 2 years, this just started the last two months of plowing, and I'd like to fix it before this years season starts. Thanks again B&B
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If you'd like to positively determine it's the relief and not a wing cylinder or wing retract valve John, either swap the reliefs side to side or swap the wing cylinder hoses and try to test it in a sand or dirt pile to see if the issue switches sides or remains. Doing so will immediately tell you where the root issue actually is rather than just replacing the relief on a guess.
     
  5. maverjohn

    maverjohn Senior Member
    Messages: 902

    Well, I swaped the hoses and the right side started doing what the left side was doing.
    pulled the relief valve and cleaned the hole thing inside and out, added new o-rings again, still the same. Pulled the check valve, screen cartridge, and both control valves, cleaned and installed new o-rings,
    still the same thing, I put the plow in full V and two minutes later the left wing will be all the way back.
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    That's a good clue. If it will retract solely on gravity alone then it's likely a leaky wing retract valve. Swap the wing retract valves side to side and check the condition of their O-rings while doing so) and retest.
     
  7. maverjohn

    maverjohn Senior Member
    Messages: 902

    Well I swapt the retract valves and replace the o-ring and the right side started retracting back and the left side
    holds now, so I know I need a new valve now, is the correct part #HYDO1637, I just want to order the right one.
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Are the valve coils black John? They should be, and if so a 1637 will fix you up.
     
  9. maverjohn

    maverjohn Senior Member
    Messages: 902

    Yes they are black, Thanks for all your help.