Final drive leak on a single side swing arm Airhead (R80G/S)

Discussion in 'Airheads' started by Malindi, Jun 18, 2013.

  1. Malindi

    Malindi Zen Adventurer

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    Hi guys,

    I am looking for some info on how to deal with a final drive leak (the big seal) on my R80G/S. All I find is info twin shock bikes. Even Snowbum doesn't have any info. I can see the seal ... can I just yank it out (how?) and replace it with the new one?

    I'm in Thailand, so have limites access to shops but BMW is getting me the part in two days for $25, so not too bad.

    If anyone in Chiang Mai has some shop space...

    Thanks
    #1
  2. Airhead Wrangler

    Airhead Wrangler Long timer

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    Really easy. Just poke a hole (or a few) in the seal and give it a few good tugs with a seal puller or other hook-like implement and it should come out without too much of a fight. I believe I banged my last one in with the butt of a screw driver. Easy peezy. No shop space necessary. You can do this one on any sidewalk in about 10 minutes if you have the right puller.

    You want the one on the left/top or something similar:

    [​IMG]
    #2
  3. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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  4. Malindi

    Malindi Zen Adventurer

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    Phew, thanks, that makes me feel better ... :-)
    Is there space behind the seal to indent it a bit inwards, as you can with a rear main seal? I don't want to damage anyhting behind it...
    #4
  5. Malindi

    Malindi Zen Adventurer

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    Also, is there an edge it seats to or do I need to eyeball it for flushness?
    #5
  6. Malindi

    Malindi Zen Adventurer

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    Yikes! No, I don't want to do that with just a tool kit ... :-)
    I'll go take a hard look at it tomorrow morning and see what size of puller I can source here.
    Thanks guys!
    #6
  7. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    been a while since I've had mine apart and I'm not sure if there is a flange where the seal will bottom out. I suspect not. The seal fits flush to the outside so just stop there, which that shouldn't be hard to judge. My concern would be rolling the seal lip, but the flange the inner part of the seal rides on sticks out a good amount so it might not be that big of a deal.

    It is quite easy to pull the cover off and remove the driven gear assembly. Undo the bolts around the cover and use two small 6mm (?) bolts to push the cover off. Looks bad in pict but it's really simple. That being said I think you can remove the seal and install fairly easy too.
    #7
  8. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    also, why do you need a puller if doing it AW's way???? Which is pretty much a road side repair. No special tools, just make sure not to go past flush w/ the seal.

    just don't be too ambitious with pocking the seal as there is a bearing behind it with a carrier for the balls. Don't push a drill or screw too deep to damage that carrier.
    #8
  9. Airhead Wrangler

    Airhead Wrangler Long timer

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    Aw, crap. I don't remember exactly what's behind that seal. I can't remember if it bottoms out on something or not. Take a photo of your current seal and then pull it out. You'll see what's inside and if there isn't anything that the seal runs into you can at least set the new one to the same-ish depth based on your photo.
    #9
  10. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    [​IMG]

    this is the best pict I have, there is a shim behind the bearing. Looks like the shim bottoms out on a flange but not the seal. The seal may bottom out on the shim. if replacing the seal with FD assembled.
    #10
  11. Malindi

    Malindi Zen Adventurer

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    Noted, thanks. I am doing it the roadside way as I won't have the paper gasket ... didn't order that.
    #11
  12. Malindi

    Malindi Zen Adventurer

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    You mean in the seal lip? I would imagine the seal itself is too tough..?
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  13. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    aw it should be fine doing it that way....I was replacing bearings when I did mine.

    NO the seal has metal in the flat part...stay away from the inner flange that the seal lip rides on as scratching that will ruin the seal once assembled.

    You'll have to drill (but not too deep) the flat part of the seal and screw in a wood screw and use pliers to pull on the screw and pull the seal out. Or pry with something at the screw hole to wedge it out.
    #13
  14. Airhead Wrangler

    Airhead Wrangler Long timer

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    No, you should be able to puncture the seal itself, just be careful not to go too deep as OLH warns above. I wouldn't try hooking anything under the lip for fear of putting a scratch in the sealing surface. Just poke a hole in it toward the outer edge with something sharp and skinny and then pull it.
    #14
  15. Malindi

    Malindi Zen Adventurer

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    Thanks guys .. I should get the seal on Thursday. Will report back here.
    #15
  16. AntonLargiader

    AntonLargiader Long timer

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    Until then, I would just take the blunt side of a knife with some thin cloth over it and sweep out the seal area. Might be all you need.
    #16
  17. Twilight Error

    Twilight Error Going nowhere slowly

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    If you can't source a real puller, I've had success using a small drill to make a pilot hole and then driving a drywall screw into the seal. Three screws, 120deg apart and pull on them with pliers a little bit at a time. Use a block of wood as a seal driver and just work your way around as you tap it in.
    #17
  18. Malindi

    Malindi Zen Adventurer

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    I think I'll be able to source a puller here. I took a closer look this morning and cleaned everything up afterwards.

    This is the leak:

    [​IMG]

    Notice the small puddle and streaming oil around the tire.

    The entire circumference of the final drive had signs of oil. The top vent stuff is not oil, it's old oil and dirt mixed.

    [​IMG]

    Inside of the wheel. Next to no oil. Shoes and running surface was dry.

    [​IMG]

    It looks like the oil came from around the seal. Noticed it dripped all down.

    [​IMG]

    After cleaning it up, I pushed back the seal a bit as Anton suggested. You can see there is some gunk build up right where the seal needs to run.

    [​IMG]

    Upon closer inspection, I could see some jagged edges on the lip of the seal near the running surface. I think the heat/not riding combo maybe deadly here and probably deteriorates rubber at a much higher pace than normal. It's been 96 to 105 here over the last few weeks/months where I am ...

    Tomorrow I should get the seal. I'm going to an outfit called Riders Corner here, run by a Brit. It's a motocycle hangout/hotel/bar/tour company. The guy seems nice, I bought a Laos map from him the other week. I'll ask him where I can do some maintenance etc. on the bike. I think it needs some TLC badly.

    To be continued.
    #18
  19. supershaft

    supershaft because I can

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    I am leery of advising using a drill. I have seen some seriously F'ed up stuff for that!! A plain old seven dollar seal puller from your local car parts store works perfectly. Then you can use that same puller on just about every seal on the bike and then some. I have two or three modified for particular seals. They work great and are cheap.
    #19
  20. driggles

    driggles Adventurer

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    I just did this on my R100RT, and used the drill, screw & pull method...drilled two small 1/16" holes at 9 and 3 oclock and screwed a sheet metal screw in about 1/4" deep. Alternate prying on each screw till it pops out. The surface that the seal lip rides against will probably be a little dirty, I cleaned mine up with crocus cloth to get it nice and smooth. The new seal will sit against an inner lip "stop" so you just drive it all the way in till it stops.
    #20