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Hitachi EX120-2 Swing motor seal

Discussion in 'Excavators' started by Tags, Oct 30, 2017.

  1. Tags

    Tags Senior Member

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    I have a Hitachi EX120-2 serial #72N-30953. The swing motor is leaking all the gear oil into the belly. I am wondering if anyone had a source or a part # for the lower seal. I do not have a parts manual and my Deere dealer isn't being very helpful. It is the same as a 490E.

    Also, does anyone have any experience/luck just putting a seal in without going through the whole swing motor? We only put 100-150 hours at the most on it screening soil at our yard. It shows 5800 hours on the meter but I have a sneaking suspicion it may have more.....thanks for any help.
     
  2. Wilson892

    Wilson892 Well-Known Member

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    Can't help with part # but my 892D had the seal pushed out by ice. Water got in the belly froze and when I swung it it pushed the seal out. If it's the same and you have no bearing issues a new one should be easy to install without going thru the whole drive.

    John
     
  3. Wilson892

    Wilson892 Well-Known Member

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    Just went to the JD parts website and if it is the same as a 490e then the part #'s are 4244693 sleeve, AT154177 seal, AT264319 oring, and AT154182 oring. After looking at the parts diagram I recall you pull the motor off the top of the gear box by pulling the gearbox bolts Then pull out the first set of star gears and carrier. You then remove snap ring on output shaft and drop it out the bottom. Take the seal flange off the bottom and install above parts and put together in reverse order. Simple when you get into it just mark the parts and put them back in same order.

    John
     
  4. Ronsii

    Ronsii Senior Member

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    We had the same problem with our seal on the swing box, the water was getting in from a torn boot for the rotary manifold.. might have taken a tree branch through it or just old rubber. Just went to the dealer and they looked it up on the computer from the blow-apart diagrams and I had it back together in ~3 hours.
     
  5. Knivens894

    Knivens894 Well-Known Member

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    I have a JD 490E purchased with the rotating motor gear oil leaking out daily. Prior owner tried to seal it by shooting grease into it. The seal was split. Pull the rotating motor and replacing the seal is a simple task. Pull out the motor, pull out the old seal, put in the new and reinstall the motor. The seal splits with age and it is no big deal to replace it. Mine had no other wear issues and has not leaked since. The hardest part is lifting out the motor.
     
  6. Tags

    Tags Senior Member

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    Great info, thanks for the taking the time to reply, I really appreciate it
     
  7. stormin

    stormin Member

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    I am having trouble getting the motor base bolts undone to lift the motor out of my Hitachi 135US. they are just bolts that should spin out aren't they? Super seized if they are.
     
  8. John C.

    John C. Senior Member

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    Most of them are have lock tight on them. You might have to heat them some to break the glue.
     
  9. Wilson892

    Wilson892 Well-Known Member

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    When I removed the swing gear from my 892 Deere I had to use my 1” impact to loosen them. They’re in tight and likely with red loctite

    Best of luck, John
     
  10. uffex

    uffex Senior Member

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    Good day
    See attached hope it is of help.
    Kind regards
    Uffex SlewMotor.jpeg SlewMotor.jpeg List.jpeg
     
  11. Knivens894

    Knivens894 Well-Known Member

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    Soak them well with penetrating oil, then take a large rod and two pound hammer, hit them each a few times, then use an impact to remove them. Without the impact a large pull handle will be required with perhaps a cheater pipe. They just screw into fixed threads.
     
  12. stormin

    stormin Member

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    Thanks for all the info. I will try the job this Saturday and let you know how it went.
     
  13. stormin

    stormin Member

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    Got the swing motor off with an impact gun and all looked good except the seal. 60.00 dollars and I should be back in business. Very cool. This is a great forum.
     
  14. Ronsii

    Ronsii Senior Member

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    Take any pics while you were in there ? we always like pics :)

    How was the inside on the ring gear area? lots of gunk/grease/water???
     
  15. stormin

    stormin Member

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    I will take some pictures tomorrow.
     
  16. stormin

    stormin Member

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    There was lots of gunk /oil/ water. 2 inches deep. any trick to cleaning the emulsion out. a drain hole is not obvious. I have been unable to google a repair/maintenance manual for my machine, any hints on where to get one? I want to keep the routine maintenance going properly. Thanks
     

    Attached Files:

  17. Ronsii

    Ronsii Senior Member

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    Yeah, sounds like most of the machines I have had experience with.... in the winter the water will freeze and cause all kinds of problems including ice chunks splintering around and gouging the seal!!!. I usually get in there after the swinger is out and machine has a bit of tilt forward to it and start shop vacing along with anything I can find to drag the sludge out... custom bent thick wire, pex pipe, etc....

    Also.... while you're in there( or near there ;) ) check the boot on top of the rotary manifold for tears/cracks/looseness and replace if possible.
     
    GregsHD likes this.
  18. stormin

    stormin Member

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    Will do. Thanks, got another suggestion to fish a rope around and drag a towel around to clean it out. I will try that.
     
  19. Ronsii

    Ronsii Senior Member

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    Yep, anything you can think of to clean it up is good, I keep a 1 gallon pump sprayer full of diesel to rinse things down with if I'm really being picky ;) as long as you're not seeing/feeling dirt,chunks of metal/rocks in there you're doing good :)
     
  20. uffex

    uffex Senior Member

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    Good day
    ToolKing is a good guy to try for a manual but I suspect you may be more able to get a J-Deer equivalent.
    Kind regards
    Uffex