Final drive oil leak

[MrRiden]

Well I finally have a problem with my LS. A Final drive oil leak appeared while the bike was on the side stand in the garage. One solitary drip of distinctively smelling gear lube decorating my rim and another hanging from the final drive. The bike had not been used in several days and I suspect I'll have to go in and take a look. Real OEM does show the O ring on the brake cam but I am not seeing a seal for the crown gear where the splines come through the inner cover. Are these the 2 places most likely to host a leak? Any tips on replacing these?
rich

[nhmaf]

These are the most likely places, but you might get lucky with this, yet...  My 82 LS started to drip a little like you described, and I pulled the wheel off and examined things carefully.   I couldn't find where the leak was coming except from one of the cover bolts (toward rear of final drive housing, at about 3'oclock position when facing the final drive from the wheel side with wheel pulled off).  There was a very slight moist area there where oil had been weeping out from the bolt hole.  I took the bolt out, cleaned it and its washer and the cover carefully, flipped the washer over and put it back, torquing it to spec.   That was 1 year ago and it has been fine ever since, not a single drip and the oil level stays right where it should.  So, do mentally prepare yourself for the "worst", but do look in there carefully and you might find the solution is much easier than you think.

[MrRiden]

nhmaf,
Had the rear wheel off and couldn't see a definitive leak but I did find similar evidence to what you report (also found your previous post on this). Took my socket and found I could undo 5 of the bolts, including the one you describe, with nothing more than my fingers and the socket / extension. The rest were not very snug either. Removed the brakes, douched everything down with cleaner and put it all back with some blue locktite. Also gave the drive splines a look / lube and all seems to be in good nick now. If anyone here has the need to have the rear wheel off give the inner cover bolts a test. I'm curious to see if this is a common occurrence.
rich
Oh, and curiously enough my LS is an '82 as well!

[Rob Valdez 79 R65]

That does not sound like a healthy state of affairs at all, Rich.  

I have lived with a leaky final drive for most of the 28 years, but not all the time, obviously.
I have never checked my cover bolts, but it has been dis/re-assembled for a new spline back in the late nineties.  (Bobs)

And are you not a believer in the centerstand for an opposed twin, for medium-length parking?

[nhmaf]

I'll keep my fingers crossed for you, Rich - I love it when a repair doesn't cost an arm or a leg, and it is very possible that you'll be good to go now for many, many miles.
 

[MrRiden]

And are you not a believer in the centerstand for an opposed twin, for medium-length parking?

Rob,
you have properly caught me being lazy! I mostly do make use of the center stand. On this occasion I had just moved the bike across the garage to facilitate work on a Bonneville engine that is going to...well, Bonneville!
   I was very happy to find the splines in excellent condition. you've got me thinking that perhaps somewhere along the line mine may have been replaced but the cover was never snugged well. Once again tho I'm really curious to hear from all who check these bolts next time the wheel comes off!
rich

[scuba]

I have had a problem with leky final drive and this was the culprit. Two o-rings at the rear brake cam 10x2mm. And for the splines, I just checked them as always when I have to open final drive and those were ok. I also have checked the rest of final drive and this is what it look like after 35000km.
Somehow I can not post more than this one picture.

[Rob Valdez 79 R65]

Only one picture per post, the way you are doing it.
If you have your pics stored on an external (on-net) server, you can put in as many as you want using the little Picture Icon at the top left of the reply screen.

[Rob Valdez 79 R65]

I has been said that the 1st gen bikes ('78-'80) do not have the slots for the o-rings on the cam shaft.  Can anyone verify?

Can a later model cam shaft be used?  Or just have a machine shop cut me some?

It seems I have heard of folks adding a 3rd o-ring...

[MrRiden]

Scuba, Rob,
I've heard of as many as 4 O-rings being employed on that brake cam shaft. I'll be keeping an eye on mine. by the way Scuba, did you ever share your work bench with Jackson Pollock? http://en.wikipedia.org/wiki/Jackson_Pollock
rich

[scuba]

Actualy, Jackson Pollack never came to visit me, but some other post modern painters did so I kept my workbench until these days

On my '83 machine, brake cam shaft has two o-rings 10x2mm but on previous '79 r75 there were 3 o-rings. I can't remember dimensions but I doubt that one can simple switch brake cam shafts without changing differential housing.

[scuba]

Thank You Rob, I'll organize my pictures on some other server 'cause I plan to do major works on my bike and to keep picture workflow of it.

[Frank_M]

Summer before this recent one I had my own oil leak in the final drive area and posted about it. I took a lot of time to discover what it was because I was hoping it wasn't something that required major surgery. The bike had set in a hot shed for a couple of months. Before the respite, no leaks. First drive out of the shed, it dumped me as I touched the brakes and there was nothing in the rear. Turns out it was what Scuba has described. I replaced the O-rings and the leak on the inside stopped, but started on the other side of the shaft. Figuring I might have damaged the O-ring there when I slipped it on, I put on another, and the problem has been solved. One other thing I noticed, though, was that the shaft had given itself a little lateral space when it was in that hot shed and perhaps that contributed to the leak.