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plow pressure

Discussion in 'Fisher Engineering Discussion' started by ramrod98, Oct 13, 2007.

  1. ramrod98

    ramrod98 Member
    from NEPA
    Messages: 44

    Hi, I have 1600 lbs pressure holding the plow in the up position. When first starting to raise the plow I had 500. I am just wondering if it is suppose to have the 1600 lbs when first lifting the plow or if i am ok ? I did take a 1/4 turn on the pump to increase the pressure hopefully to 1750 but have not tried it yet as I am chaning the fluid first. Any help would be appreciated. I did see some aluminum shavings in the filter of the pump which must be from the pump.
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    You check the pump pressure at the end of the cylinder travel with the pump still running...this is your MAX pump pressure you want to set. Checking the pressure at any other point in the stroke isn't valid...
     
  3. CNY Plow

    CNY Plow Senior Member
    Messages: 145

    check the fisher web site.
    they have tech data for all their pumps.
    so, you lost pressure but did not lose fluid - did you pressurize the pump and re fill it (move the blade up down side-to-side)
     
  4. ramrod98

    ramrod98 Member
    from NEPA
    Messages: 44

    I didn't lose pressure at all. I was just checking my pump out to be sure it was still good before the start of the season. I thought the pressure was taken at full travel(holding the lever up for a second after fully lifting). I have 1600 lbs which is within the limit. I was told
    1750 is best. I took a 1/4 turn to increase pressure but have to get fluid tomorrow before retesting. I cleaned out the old fluid today. I did have some shavings in the filter which worried me a bit. Probably a good idea to buy a spare pump just in case i get broke down while plowing.
     
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    I'm assuming your working on an older style SEHP power unit here..

    Set the pump pressure to 1850psi

    If the pump will develope 1850psi then it's in good shape.

    For future reference, a 1/4 turn on the relief screw will change the output pressure by about 200-250psi

    You didn't say how much shavings you actually found but don't worry about it if it was a small amount....totally normal on a used pump. They're from the sealing ring on the lift piston sliding in the lift housing, not directly from the pump itself.
     
  6. ramrod98

    ramrod98 Member
    from NEPA
    Messages: 44

    Yes, it is a 95 minute mount plow. It is still going strong with no problems for all of these years. It has been through some very heavy use. I only ever changed one pump on it in all these years. The outside of the filter was pretty full of very small shavings(aluminum grit). I think that I should get the old fluid out of the angle cylinders also before refilling the unit. I will try for the 1850 psi. Thanks for the help. I really appreciated it.