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Recent content by qwertylad

  1. Q

    Hitachi ex120-3 cavitation/aeration

    Ok, interesting idea. I've also been meaning to look at the fluid flowing to see if it comes out differently depending on the function. Will have to do that tomorrow. Thanks
  2. Q

    Hitachi ex120-3 cavitation/aeration

    I did this a while ago, and it was about 1/2 the speed it should be. The pump still can't push as hard if the oil is too aerated, though. So can you really say it's the pump's fault just by its output? On another note, the problem is not nearly as bad since flushing the system of the old cheapo...
  3. Q

    Hitachi ex120-3 cavitation/aeration

    Wow, didn't think of that. I just took the screen out for a test run, but it's been in the machine otherwise. No new attachments, just an old hydro thumb. I didn't bleed the pump the first time. After a while I did take that Allen bolt out of the top of the pump at idle. The fluid coming out...
  4. Q

    Hitachi ex120-3 cavitation/aeration

    I see there's a "make up valve" that lets fluid flow into the swing device when it's turning on inertia. The manual says this is to prevent cavitation at the pump. Maybe I'll pull the line and valve to make sure they're clear.
  5. Q

    Hitachi ex120-3 cavitation/aeration

    I have my doubts that it's actually pulling air in before the pump. There's a lot of pressure built up in the reservoir after use, which I would expect to force fluid out of any leaks in that big pipe. However, don't know where else air would be entering the system. Other suction lines? Do...
  6. Q

    Hitachi ex120-3 cavitation/aeration

    Some extra info: Machine is a grey market 97, I believe 8k hours Engine runs great, no stalling or bogging. I've just started running the machine again after sitting for the winter. Had to clean the fuel tank out to get it going properly.
  7. Q

    Hitachi ex120-3 cavitation/aeration

    Hello all, looking for some help diagnosing my old beater. In the past few hours of use, the machine will whine like it's out of fluid under heavy load, particularly when swinging, but eventually with any function. Power is about 1/2 what it was before issue. The hydro tank is very bubbly after...
    • qwertylad
    • Thread
    • cavitation ex120-3 hitachi hydraulic
    • Replies: 11
    • Forum: Excavators
  8. Q

    Hitachi EX100-3 Overheating

    What parts were needed here? Did you have to reseal the pilot pump and valve block with new springs to get pressure back up?
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