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Hitachi 75 issues

Discussion in 'Excavators' started by Dackdack, Dec 1, 2019.

  1. Dackdack

    Dackdack Member

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    hey everyone, I’ve been having some issues with my machine since having the center joint seals done(75 hitachi ex ur). I’m not sure if these are related but hopefully you can help. The power in my tracks is reduced fairly significantly even when cold and after operating for awhile my hydraulic oil is very hot. The system appears to be under a lot of pressure when I remove the cap on the hydraulic tank it basically will launch the cap. Today I also noticed one of my final drives is very hot. I’m not overly experienced with excavators but I’m fairly handy so I’m wondering if you guys could point me in the right direction. I don’t know if these symptoms could be caused by the same thing or if I’m chasing multiple issues. These issues didn’t exists before i had my center joint and swing drive seals done. Thanks
     
  2. uffex

    uffex Senior Member

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    Good day Back
    You should have pressure in the tank so thats not so alarming finding out why your tracks lack power requires trouble shooting process, if you are happy to guess that can take more time but you indicate that the rebuilding of the central joint was when the issue began maybe something has been missed.
    Kind regards
    Uffex
     

    Attached Files:

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  3. Dackdack

    Dackdack Member

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    Yes I believe that is when the change happened. I am going to chat with the shop that redid the seals today. One other issue I am having is one of my final drives is very hot after operating. Could this be caused by the center joint or is it more likely this is a different issue? I am going to change the oil in that side today to be sure it’s good.
     
  4. uffex

    uffex Senior Member

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    Good day Dack
    The correct way to check out the central joint is to measure the leakage I will see if we have some information on file to help - when you say that a final drive is getting hot I guess that statement is in comparison to the other side. In normal circumstances both should maintain the same tempreture, I would suggest when you drain down the planetary you observe what comes out, our experience has shown high content of base metal and this should not be to alarming however in your situation it may be wise to dismantle and inspect if you cannot see any obvious cause.
    I can recall one similar experience where a welder had rebuilt the sprocket teeth with the ground lead connected to the track chain, the main bearing was not to happy about being welded to the outer raceway but that instance is unusual.
    Kind regards
    Uffex
     
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  5. uffex

    uffex Senior Member

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    Good day Dack
    Attached is to some information that may be of help.
    Kind regards
    Uffex
     

    Attached Files:

  6. Dackdack

    Dackdack Member

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    Thanks for the link. Yes one final drive is very hot to the touch. The other is barely warm. I’ll start by checking the oil.
     
  7. excavator

    excavator Senior Member

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    Is it possible that your case drain hose from the hot motor got kinked or plugged? Possibly connected wrong?
     
  8. Dackdack

    Dackdack Member

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    I will have to check that out. I just did some reading online and it could be a possibility. Does it run from the final drive to the center joint ? Or where does it go?