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9ft Unimount will not go up all the way, help please!

Discussion in 'Truck & Equipment Repair' started by Joeynapp, Oct 16, 2016.

  1. Joeynapp

    Joeynapp Junior Member
    Messages: 3

    I have an 9ft unimount and the plow will go up about 6". When it goes up that 6" the motor sounds like it would if it was all the way up. I have cleaned the pump and filter, replaced pump housing and cleaned it thoroughly. tried a motor and pump on a working 8ft blade, still didn't work. Checked all valves getting 6-10 ohms on all cartridges hooked them up to a battery make sure I heard the click. Valves move freely, re adjusted cusion valves thinking that might have something to do with it and it doesn't. I'm lost and have no clue what else to do. Does a 9 ft blade have a stonger pump or motor than an 8ft? It almost seems like the ram isn't getting enough juice to push it up all the way. It angles fine and will stay up and not droop down at all over night. I don't have a hydraulic pressure gauge, but just ordered one. Is there something I'm missing like bleeding the valve body? I bleed the system by leaving the fill nut off and angling left/right 10-12 times each way. Any help would be greatly appreciated.
     
  2. Dogplow Dodge

    Dogplow Dodge 2000 Club Member
    from NJ
    Messages: 2,981

    My unimount pro plow holds my 8.5 plus wings. The pump has no problem lifting it at all. A brand new internal hydraulic pump was purchased from western and when I installed the pressure gauge, it was not set properly from the factory. I had to pull the motor and adjust it a few times till it was within spec.

    What unimount unit do you have ? Isamark III? Did you try bypassing the controller with a jumper wire to each coil? Ensuring that the coils move the blade accordingly ? After you bled the system ?

    The small o ring below the internal pump should be checked to make sure it's not out of place, damaged or flattened. Worn out pump can be an issue. How old is the internal pump? The a frame isn't binding ? Try using a floor jack to raise it up manually.

    When I purged the lines, I did not have the fill plug loose and I placed the a frame up in the air with a floor jack before I cycled left and right, purging the angle cylinders. Check fluid level often during the process, lift piston all the way down.

    If your lift piston is scored, or the seal pack is either worn, damaged, or installed oriented incorrectly, you could be losing pressure as it moves upwards. You will see this in numerical value on the pressure gauge.

    Just throwing a few ideas around
     
    Last edited: Oct 16, 2016
  3. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,972

    Need to put the gauge on it before you do anything else.....And for heaven's sake, STOP MESSING WITH SCREWS AND ADJUSTMENTS. Goto westerns website and get your manuals
     
    Dogplow Dodge likes this.
  4. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,669

    Post pics with plow up and down. Are chains adjusted correct?
     
    Joeynapp likes this.
  5. Randall Ave

    Randall Ave PlowSite.com Addict
    Messages: 1,985

    Had one last year, the frame was worn so bad the lift frame was leaning forward. There geometry off, would not go up good. Leave the cusion adjust ments alone. Send a few pics, need a pressure gauge reading.
     
    Joeynapp and Dogplow Dodge like this.
  6. Dogplow Dodge

    Dogplow Dodge 2000 Club Member
    from NJ
    Messages: 2,981

    D
    Yup.. Chains out too long will do the same thing..
     
  7. Randall Ave

    Randall Ave PlowSite.com Addict
    Messages: 1,985

    Yup, if the chains are to long the down pressure will never work.:dancing:
     
    Joeynapp and LapeerLandscape like this.
  8. LapeerLandscape

    LapeerLandscape PlowSite.com Addict
    Messages: 1,611

    If the chain is adjusted correctly lift the plow the 6inches and put a floor jack under the middle of the blade then unhook the chain and see if the ram goes up all the way like it should. If it does then lift the jack and make sure the blade can go up and down freely. If those two work like they are supposed to then its in your valving or pressure.
     
    Joeynapp likes this.
  9. SnoFarmer

    SnoFarmer PlowSite Fanatic
    from N,E. MN
    Messages: 8,556

    its a chain lift, it well never go as high as a direct lift.
     
  10. Randall Ave

    Randall Ave PlowSite.com Addict
    Messages: 1,985

    There's TV commercials now says they have little blue pills that will help!Thumbs Up. Running off the tracks any minute now.
     
    Joeynapp likes this.
  11. Joeynapp

    Joeynapp Junior Member
    Messages: 3

    Thank you for all the responses. Its a isermatic pump. The chain is adjusted right. I never adjusted the pump. I only the cushion valves to spec via the manual 1-3/4 turn on each.

    I jacked up the plow made sure the ram was all the way down and put the chain on would still go only up 6 inches. With the chain disconnected it would shoot up all the way no problem. I changed the housing and I checked the seals on the lift ram and they are in great shape.

    It should only be the s3 valve when lifting and lowering correct?

    I will get pictures tomorrow when I get back to the shop.

    Thank you again all for the responses!

    I also added the blue pill to the hyrdrolic fluid but it would only stay up for 4 hours :).
     
  12. LapeerLandscape

    LapeerLandscape PlowSite.com Addict
    Messages: 1,611

    If it stays up longer then that take it to a mechanic..:mechanic: