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Final drive seal

Discussion in 'Excavators' started by philsbs, Apr 2, 2008.

  1. philsbs

    philsbs Member

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    Location:
    Northern WI
    Has anyone ever replaced the floating final drive seal on a smaller excavator (Komatsu PC50UU-2)?
    The big o-ring in back of the floating seal was broke causing the oil to leak out when filled to that point. I got a new seal and want to know if there is a special procedure for installing it. I have not been able to locate a service manual for this model.
    Thanks, Phil
     
  2. stevinmonteur

    stevinmonteur Active Member

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    Occupation:
    mechanic
    Location:
    nw vennep, the netherlands
    life-time seal

    Hello Phil

    clean the o-ring chambers in the housing and sprocket with grinding paper and steel brush. place the life-time seal with the o-ring in the chambers using a screwdriver to pop the o-ring in ( do not use grease or oil ) clean the surface of the life-time seals and oil it and assemble the sprocket on the shaft.

    marco
     
  3. philsbs

    philsbs Member

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    Hi Marco, Thanks for the quick reply.

    My concern is how deep the o-ring should be in the chamber. The seal has a groove were the o-ring seats but the housing is tapered. If I try to push the o-ring to far in the in the chamber the seal will pop out. If I push the o-ring in just below flush the seal stays in place so I assume that is the correct depth.

    Thanks again, Phil
     
  4. John C.

    John C. Senior Member

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    Machinery & Equipment Appraiser
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    The term floating seal is one I haven't heard. Do you mean the sprocket seal of the cap seal on the front of the final?

    As I recall that machine uses the HighDash final which is a pin and cam arrangement inside.

    The sprocket seal requires that the final drive be completely disassembled. You should be able to get a parts breakdown from the Komatsu dealer. A book might be more of a problem.

    Good Luck!
     
  5. philsbs

    philsbs Member

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    Nov 21, 2007
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    Hi John,
    I believe this would be the sprocket seal. Its the main steel face seal behind the final drive cluster. They call it the floating seal in the parts book (dealer faxed me the breakdown).


    The cover comes off, then snap ring on shaft, then three bolts holding the cluster in and the sprocket housing will seperate from the motor housing to get at the seal.
     
  6. bigbob

    bigbob Well-Known Member

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    Location:
    Lee,NH
    A few years back I replaced the Duo Cone seals on the Hy Dash drive motors on my 94 Cat 307. Remove the whole drive assembly to facilitate replacement. IF YOU DO NOT HAVE A SHOP MANUAL, TAKE IT TO SOMEBODY WHO HAS DONE IT BEFORE. If you screw it up they are about $5k each. I had the shop manual and still had to have the dealer seat the o rings with a special tool.
    The o rings on the cover are easy. The hard part is getting the snap ring out, then prying the cover off. You can blow the cover off with low pressure air thru one of the fill holes.
     
  7. John C.

    John C. Senior Member

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    philsbs,
    It's been a long time but if I remember correctly there are about thirty dowel pins that ride in the carrier but will fall out when you tip the final up to pull out the motor.

    When I did them, seating the seal was easy as long as the grooves the o rings sit in were clean. The hard part was turning the assembly over and loading the carrier and pins back in place.

    Yours might be just a planetary box and if so those are pretty simple. You should change the brass thrust washers while you are in there.

    Do you have a photo or two to help and old man's memory?
     
  8. tctractors

    tctractors Senior Member

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    Hi Dash,

    The Duo Cone seals are floating and set there own depth as required, all the Hi-Dash gearbox's I have ever repaired (smallest I go is 13t) all need re timing of the of the outer gears, they have 2 lines on each gear , they must all face north and the central gear needs to be a loose fit as it matches up with the other gears.

    tctractors
     
  9. philsbs

    philsbs Member

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    Location:
    Northern WI
    Thanks to all who have responded. I am happy to say the drive is back together, timed and back in the machine with no leaks.

    Thanks again, Phil
     
  10. Dauber

    Dauber New Member

    Joined:
    Jan 30, 2012
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    Location:
    SW IN
    Question for bigbob or others. I have a 1994 307. The seals on the outside cover plates of the Hy Dash final drives are leaking. Any advice on getting the snap rings out? Is the best way to pry the covers off by using air pressure? Do I need to take the tracks off if I just remove the outside covers? A rookie Cat mechanic (he is still in school) is telling me I have to take the tracks off and go through the inside of the drive motor to get the cover off. I am not sure about that.
     
  11. bigbob

    bigbob Well-Known Member

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    You have to remove the snap ring in the outer edge of the cover to get the cover off. Hit it with blaster or another rust breaking product. You do not have to remove the tracks, but it may help to remove a few track pads for easier access. I used two small flat blade screwdrivers to remove the snap ring. Clean the groove out well with a wire brush first. Get new snap rings and rubber o ring seals at Cat. I have used compressed air to remove the covers, turn the pressure way down though. I change the oil inside every year, doesn't take much. I use the Cat TDTO Oil as recomended by the manual.
     
    Last edited: Jan 30, 2012
  12. Dauber

    Dauber New Member

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    OK we'll try that out. Thanks a lot!