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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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    BA34656A-6BF2-4887-BD90-CD51649ECDF8.jpeg 72011C5D-FF13-4997-A8E5-E8819DD60BFF.jpeg Was losing a lot of fluid at swing motor so Pulled the swing motor to replace seal

    Is there anything else to check for once I’m in there?

    also, is there more than one seal tht could be the culprit?

    attached picture- is the seal #35 all I need?
     
  2. uffex

    uffex Senior Member

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    Good day
    I recommend you check the swing bearing movement, this can cause the bearing to fail in the bottom of the swing transmission. Not sure what has happened to your thread, strange attachment maybe gone wrong.
    Kind regards
    Uffex
     
  3. Tones

    Tones Senior Member

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    As Uffex said. A failed seal is usually a symptom not a cause.
    My guess is #35,37, 21,20.
     
  4. shelbyk7

    shelbyk7 Well-Known Member

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    Okay pulled swing motor and #35 seal is bad

    i had ordered a swing motor seal kit but it did not have this seal, had a much smaller seal with other orings (pic attached)

    is there anything else to look for while it’s out? Best way to check the bearings? Will it be obvious? C7B078FE-27FF-424E-967B-8C507FE183BD.jpeg D6B3435B-8C89-4DD2-A332-8EF4360A3DFB.png 74026819-6C8C-4CC1-8128-AA0B0F412099.png
     
  5. Kobelco ireland

    Kobelco ireland Senior Member

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    They sent you a seal kit for the swing motor instead of the swing gearbox
     
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  6. shelbyk7

    shelbyk7 Well-Known Member

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    So what are some symptoms of needing seal kit for the swing motor? Trying to see if I need it

    Do they have “kits” for the gear box?

    I purchased a new seal for gear box what else should I get?

     
  7. Kobelco ireland

    Kobelco ireland Senior Member

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    Are you losing gear oil from the gearbox or is the gearbox filling with hydraulic oil
     
  8. shelbyk7

    shelbyk7 Well-Known Member

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    Well I’m not entirely sure if hydraulic is in gearbox,

    i pulled it because the gear oil kept running out and would bogey low on dipstick

    also when I pulled motor and gearbox (all together) a lot of water is in the turn table

    i loosens a couple bolts underneath it but still water standing ?
     
  9. Kobelco ireland

    Kobelco ireland Senior Member

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    If the gear oil is leaking out of the gearbox then you need the big main bottom seal(part #35 in parts diagram) and you need to check for play in the bearing. The water in the grease bath can be drained from underneath the machine through an opening in the frame covered with a small rectangular plate.to access this plate you need to crawl under the machine between the two tracks and look up through the hole in the bottom of the under carriage towards the turning joint
    And you should see a small plate held on with two bolts.
     
    Last edited: May 23, 2022
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  10. uffex

    uffex Senior Member

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    Good day
    Attached may be worth a check.
    Kind regards
    Uffex
     

    Attached Files:

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  11. shelbyk7

    shelbyk7 Well-Known Member

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    Checking for play in the turntable, do bearing #21 and #20 go out very often?

     
  12. uffex

    uffex Senior Member

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    Good day Shelby
    Much depends on care external causes of failure includes striking electric cables, over bucketing, water ingress. Checking will give peace of mind that the gearbox repair will not fail for that reason, additionally to knowing how much worn the bearing is at.
    Kind regards
    Uffex
     
  13. shelbyk7

    shelbyk7 Well-Known Member

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    Thank you

    honestly, I do not have the means to remove the cab completely to change the giant roller bearing. Unless it was absolutely terrible I don’t think it will be changed unless I spent some time gathering some equipment to do it. I’d like to know if I’m in spec though so I will try to get that done

    in regards to water in the belly, the center joint which has a rubber cover around it, is not sealing to the metal really well. (Picture below ) can that cause water to get into any spots it shouldn’t be?

    I had something else come to mind

    on the left joystick , a wire has been cut or broken and not repaired. (Picture below)

    also a (black w/ yellow stripe)wire running up side of the boom (left side if sitting in seat) also has been torn off. What is this for?



     

    Attached Files:

  14. shelbyk7

    shelbyk7 Well-Known Member

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    So I got the swing motor seal kit and didn’t occur to me at the time that it wasn’t considered all one piece with the gear box

    So now im needing all of the orings on the gear box, I did order the big seal on gear box already

    I am not having luck finding a kit with these orings? And having hard time finding them at all

    this attached drawing is of a ex200-2 but it comes up when I select ex120-2

    so I need all orings in the diagram

    anyone have idea of where to get a kit or where to order individually tht would come in quickly ?
     
  15. shelbyk7

    shelbyk7 Well-Known Member

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    How much play should the shaft #3 in diagram have? Trying to determine roller bearing is okay or not

    The splined end of shaft (closest to bearing moved .024”

    pic below
     

    Attached Files:

  16. uffex

    uffex Senior Member

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    Good day
    If I have followed the illustrations correctly, the 0.024" you are recording is at the output of the motor. Unless hydraulic fluid is filling the transmission, there is little to be concerned. The actual measurement I do not find alarming.
    Kind regards
    Uffex
     
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  17. shelbyk7

    shelbyk7 Well-Known Member

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    Thanks I wanted to be sure while it was apart

     
  18. shelbyk7

    shelbyk7 Well-Known Member

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    Can this be washed out with a hose by chance? Kinda nasty in there , any best practices,?

     
  19. maineplower

    maineplower Well-Known Member

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    I bought a cheap small shop vac and vacuumed it out while I had the swing motor out. Then threw the vacuum out.
     
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  20. uffex

    uffex Senior Member

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    Good day
    I would suggest dilute what is left after draining with some parrafine or similar, if you can hire a hot pressure wash to clean up.
    Kind regards
    Uffex