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Komatsu D21a-7 steering clutch

Discussion in 'Dozers' started by Don Shilling, Oct 30, 2019.

  1. Don Shilling

    Don Shilling Well-Known Member

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    Today I removed the covers over the steering clutches. After removing the brake band springs and all 16 of the flange bolts. the clutch assembly is loose and tries to come out but something is snagging as I try to lift the clutch assembly upwards. I'm missing something and the manual is very lacking in details.
    Hopefully, someone will have a suggestion or trick to remove the clutch.
     
  2. Don Shilling

    Don Shilling Well-Known Member

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    The manual is telling me to remove the "clutch pilot" and the clutch will lift out. I don't know what this "pilot" thing is. Can anyone enlighten me? How much movement should the throw out lever have?
     
  3. epirbalex

    epirbalex Senior Member

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    there could be some info in the link I posted for you on your last thread about dry clutches
     
    West12 likes this.
  4. Don Shilling

    Don Shilling Well-Known Member

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    I don't see a link anywhere.
     
  5. epirbalex

    epirbalex Senior Member

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  6. Don Shilling

    Don Shilling Well-Known Member

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    I found it! Flushing the clutches brings up another problem. Would that not flush the grease out of the throw out bearing? My clutches are 254 years old and never worked on. I want to take everything apart, clean and replace all discs, drums, springs, and throw out bearings and make the assembly work like new. I noticed about 2 inches of crud in the bottom of the housing that needs to be cleaned out. My problem now is trying to lift the clutch pack up and out of between the flanges.
     
  7. epirbalex

    epirbalex Senior Member

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    Thats a lot of rubbish to have there for a closed system , the pilot gear refers to what would have been called thrust control , control probably wrong name for it . Check to see that one or more plates have not leaned over againt a flange , are there dowels catching against the drum . Should come up with a good yank . Sounds like you are not in there too early .
     
  8. Don Shilling

    Don Shilling Well-Known Member

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    I worked on the right clutch today but still haven't managed to remove it. Maybe if the throw out arm could move a bit more to the left, (center of the tractor) I might have enough clearance. I think I'll try to remove the left clutch and see if it has the same problems.
     
  9. muzy

    muzy Well-Known Member

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    Hi, just reading along here. Could the thrust bearing be the pilot or thrust control? If your throw out arm is connected to a bearing, could it move further if you disconnected it?
    cheers
     
  10. Don Shilling

    Don Shilling Well-Known Member

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    Hi Muzy! From what I can discern, the steering clutch must be removed in order to remove the inboard flange to access the throw out bearing. I think the throw out arm needs to move toward the center line of the tractor and touch the edge of the top opening. I still have over a half inch of arm travel to free up.
     
  11. muzy

    muzy Well-Known Member

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  12. Don Shilling

    Don Shilling Well-Known Member

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    I got it out! It was just a matter of freeing up the throw out arm and moving it farther away from the clutch pak. It's pretty nasty in that cavity and plenty of rust and crud. The parts don't seem to be unusually worn, just years of neglect and contamination getting in from bolt holes that are supposed to be sealed with cork plugs. How do put pics on this post?
     
    muzy likes this.
  13. Don Shilling

    Don Shilling Well-Known Member

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    I need to remove the flange from the bevel gear shaft. I removed the lock keeper and ready to remove the big nut. Does anybody know what is the wrench size for the big nut?
     
  14. Don Shilling

    Don Shilling Well-Known Member

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    [​IMG]
     
  15. Don Shilling

    Don Shilling Well-Known Member

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    It's nasty in here! Years of neglect and moisture but I have a beadblaster. I intend to repair and rebuild to like new condition so I won't have any surprises when it goes back together![​IMG] [​IMG] I had to use a hydraulic press to dissemble this actuating lever assembly. It was badly frozen tight!
    [​IMG]
    The brake band had corrosion between the band and linings causing the linings to crack and break apart at the rivets. New parts coming.

    [​IMG]
     
    Last edited: Nov 9, 2019
    muzy likes this.
  16. Don Shilling

    Don Shilling Well-Known Member

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    Nice thing about having a glass bead blaster! [​IMG][​IMG]
     
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  17. Don Shilling

    Don Shilling Well-Known Member

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  18. Don Shilling

    Don Shilling Well-Known Member

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    Still cleaning and prepping parts for the steering clutch overhaul. I've got the nuts off the inboard flanges but they are super tight. I have a spreader bar attached as a puller and considerable strain applied with penetrating oil soaking the shaft. Next I'll use a porta power spreader jaw between the flange and throw out arm to try to move it.
     
  19. Don Shilling

    Don Shilling Well-Known Member

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    In removing the inboard and outboard steering clutch flanges I used a puller bar to good advantage as shown.
    [​IMG]
     
    Last edited: Dec 8, 2019
  20. Don Shilling

    Don Shilling Well-Known Member

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    Considering the prices, I took another look at the brake drums. After beadblasting and polishing on the lathe, I saved several hundred dollars!
    I used a portable 21" belt sander to dress the outside surface. All the internal teeth were perfect.
    [​IMG]