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Loader Arms

Discussion in 'Wheel Loaders' started by KAC=CATeater, Apr 19, 2010.

  1. KAC=CATeater

    KAC=CATeater Member

    Joined:
    May 22, 2009
    Messages:
    13
    Location:
    Northeast
    Hey, got a Komatsu WA380-6 that all of a sudden had low work equip pressure. I tried to adjust the main up but it did nothing. The unload p is also lower than spec, ppc pressure is 20 psi from spec (pretty close). If you put the throttle all the way down, the arms can be lifted up. If you dont, they dont move. Bucket curls with out throttling up but is very slow. Think a main relief would be doing this?
     
  2. Chris5500

    Chris5500 Well-Known Member

    Joined:
    Oct 23, 2009
    Messages:
    217
    Occupation:
    Plant Mechanic
    Location:
    Australia
    I assume you were using a gauge when you tried to adjust the MRV pressure?What's your actual MRV pressure set to at the moment?
     
  3. KAC=CATeater

    KAC=CATeater Member

    Joined:
    May 22, 2009
    Messages:
    13
    Location:
    Northeast
    Yes, a digital tifco gauge. It is at 3400psi right now. should be at 4350+-220.
     
  4. Chris5500

    Chris5500 Well-Known Member

    Joined:
    Oct 23, 2009
    Messages:
    217
    Occupation:
    Plant Mechanic
    Location:
    Australia
    Pull the MRV cartridge out and make sure there's nothing blocking the jet bore, if it is blocked then adjusting the pilot spring will have nil effect and the relief cracking pressure will be considerably lower.

    Have you tried adjusting your PPC pressure? If not then check it too for blockage.

    Could well be something on its way out and contaminating the system.
     
  5. KAC=CATeater

    KAC=CATeater Member

    Joined:
    May 22, 2009
    Messages:
    13
    Location:
    Northeast
    I did some more troubleshooting on it and decided it must be the the MRV. Put a new one in it and prob went away. FYI.
     
  6. CTXINCCONST

    CTXINCCONST New Member

    Joined:
    Dec 15, 2011
    Messages:
    1
    Location:
    Connecticut
    Hello,
    I have some questions about this same loader if its still up for discussion. I have a WA380 with about 4500 hours on it. it has the Cummins engine Cid/L 505/8.3. We have owned it about 6 or 7 months, bought it from a Komatsu Dealer locally. Anyways the crank shaft broke couple days ago. Any experience, has anyone had this problem??? Thanks\
     
  7. Davvinciman

    Davvinciman Well-Known Member

    Joined:
    Nov 29, 2011
    Messages:
    82
    Occupation:
    Operating engineer and business owner
    Location:
    So. California
    Another cause of problems of this type is if you have an O-ring disintegrate into the hydraulic system and pieces can get lodged in the relief or control valves. And to flush a hydraulic system is a real pain. It's the one 25 cent o-ring that can take down the million dollar machine. Glad you found your problem.
     
  8. >HevyIndsMFGng<

    >HevyIndsMFGng< Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    45
    Occupation:
    Mechanic/Student
    Location:
    Oshkosh, Wis
    A thank you to Chris 5500 would have been nice... -.-