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Hitachi ex120 swing motor leaking (what else to look for?)

Discussion in 'Excavators' started by shelbyk7, Apr 11, 2022.

  1. shelbyk7

    shelbyk7 Well-Known Member

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    If no accesss to hot pressure washer, will cold pressure washer work?

     
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  2. uffex

    uffex Senior Member

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    Good day Shelby
    I would suggest make the best of what you have availible, normally the Parafine (Kerosene) will clean up reasonbly well.
    Kind regards
    Uffex
     
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  3. shelbyk7

    shelbyk7 Well-Known Member

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    Okay, that’s what I was confused about, I thought you were saying paraffin, the wax and couldn’t make sense of it

    i do have kerosene ,thanks

     
  4. shelbyk7

    shelbyk7 Well-Known Member

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    Getting ready to add fluids back into machine

    Is there anything special I need to do? I drained pump and tried getting all the fluid and it because the fluid was nasty

    put some in swing motor before installing it.

    Anyway I Can put any in pump before starting it up?
     
  5. shelbyk7

    shelbyk7 Well-Known Member

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    Also. uFFEX

    i rebuilt fuel pump, it had an electric in line when I got it

    rebuilt it, would it hurt to leave the electric just to assist? Any diagram for how fuel lines and system should be routed?

    Not sure if original owner bypassed the mechanical lift pump or not when went electric
     
  6. uffex

    uffex Senior Member

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    Good day Shelby
    I cannot be sure regarding third party fuel pumps however I have attached all the illustrations I have with regards to the fuel system. Pumps & Motors make sure you flood - bleed the body of the units before you crank the motor - run the engine at idle for a short time to clear any remaining air or ingress.
    Kind regards
    Uffex
     

    Attached Files:

  7. shelbyk7

    shelbyk7 Well-Known Member

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    So the electric fuel pump brand is-
    “ Facet Posi-Flow”

    Here are the specs, not sure what exact model is in mine but looking today . Is 10psi enough ?

    Available Features

    • 12 inches minimum dry lift
    • 23 - 40 GPH
    • 1.5 - 10 PSI
    • ESD compliant
    • 1.5 amp average
    • Diesel Priming and Self Regulating
    • Light-Weight - Compact
    • Internal 3.5 amp fuse
     
  8. skyking1

    skyking1 Senior Member

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    my early JD120 is about equivalent to a 120-3
    The tub in mine was not a separate piece, it is all integral welded stuff.
    I did not get pictures, but the swivel is mounted in a raised up area with a rim on it. The water may be sitting on just that upper area. I had a small amount that rained out on me when I pulled the swivel, but no signs of water in the main tub area where the slewing gear runs.
     
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  9. shelbyk7

    shelbyk7 Well-Known Member

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    Thanks

    i have found this sensor leaking onto the tracks behind the cab. Some kind of Pilot sensor? It’s kind of busted open and leaking at the break. Picture below,

    Is this important for function? Or can it do without?
     

    Attached Files:

  10. skyking1

    skyking1 Senior Member

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    That's hard way Jones to pull it and find out. I would tend to get one coming and err on the side of "putting it back how they designed it", rather than try the weight reduction program method.
     
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  11. shelbyk7

    shelbyk7 Well-Known Member

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    Fair enough, i just had some panels off and doing maintenance when I saw it leaking pretty good amount.

    Seperate of this thread is the machine was having some normal ex120 issues of jerky controls and saw this as I was doing some other stuff to it and was curious if this sensor would cause issues if it were bad

    i appreciate all the help, first excavator and I’m definitely a rookie. It’s taken awhile to go through it and I’m just ready to get her going
     
  12. skyking1

    skyking1 Senior Member

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    If you don't have records of it, I would suggest doing a full 2000 hour service on it. That's all the fluids and filters, coolant, check everything. Get a service manual for the procedure.
    It's about 700 in parts and pieces but if you can't see where it has been done that is money well spent.
    I cannot diagnose "jerkiness" as I have not experienced it, but it could be due to things like that leak on the pilot circuit, or plugged pilot filter. Getting things fresh and clean will eliminate those as the source of the problem.
     
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  13. shelbyk7

    shelbyk7 Well-Known Member

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    Great, that’s what I’m doing at the moment

     
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