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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Motorhobo on April 13, 2017, 06:21:00 AM

Title: Final drive leaking gear oil into cavity
Post by: Motorhobo on April 13, 2017, 06:21:00 AM
I have three spare final drives lying around and they all leak some gear oil into the spline cavity. It doesn't leak out between the mating surfaces of the FD and swingarm, but every 6000 miles when I pull the FD to replace tire/lube splines a bit of gear oil is visible in there, maybe a teaspoon or so. So I'd say I'm in need of a seal replacement but not sure which one. I've read this:

http://www.motobrick.com/index.php/topic,7029.0.html

And what I can say for sure about that procedure is, maybe I can do it but odds are good that I won't. The cost-benefit of that action justifies taking it somewhere and paying the whatever...

Despite the little bit of fluid, the splines are adequately lubed and it doesn't appear that that bit of gear oil is washing the lube (Guard Dog) off the splines. So the question is, am I the only one with seepage past whichever seal that is and what's the I-can-live-with-that tolerance there? And what is the likelihood of that seepage resulting in failure that will kill me or my driveshaft or both?

Comments appreciated...

MH
Title: Re: Final drive leaking gear oil into cavity
Post by: Laitch on April 13, 2017, 07:18:52 AM
And what is the likelihood of that seepage resulting in failure that will kill me or my driveshaft or both?
Comments appreciated...
As long as you keep aware of the drive's gear fluid level, I think the likelihood of failure would be low until it leaks at a rate greater than your intervals of checking can discover. I'd make the decision for repair when fluid starts leaving the assembly for road and bike surfaces, or fluid loss starts exceeding my will to check for it. Eventual repair or replacement is in the cards.

My tolerance for defects in this category is high.
Title: Re: Final drive leaking gear oil into cavity
Post by: johnny on April 13, 2017, 07:41:46 AM
greetings...

when whacking... chopping... sliding... high siding... you gonna getts a little in there...

everytime i getts in there i find some mobil 1 gears oil...

when it looks like this you gotts some whack...

(http://i236.photobucket.com/albums/ff192/owrstrich/2011/11-06-12%20Jockos/173.jpg)

j o
Title: Re: Final drive leaking gear oil into cavity
Post by: Motorhobo on April 13, 2017, 07:57:32 AM
Cool, thanks Laitch and Johnny -- one less thing to worry about.
Title: Re: Final drive leaking gear oil into cavity
Post by: The Mighty Gryphon on April 13, 2017, 08:56:39 AM
I had the same problem with my RT a couple years ago.  About 2 tablespoons in the swing arm when I went in for a spline lube.

Because I needed a special fixture and a wrench for the nut, I took the final drive to an independent BMW shop and they replaced the seal for $100.  When I figured in the time and cost of the stuff I needed to get, the job cost me maybe $30.
Title: Re: Final drive leaking gear oil into cavity
Post by: Motorhobo on April 13, 2017, 10:01:38 AM
That'd be great except I don't know of an 'independent BMW shop' in my neck of the woods, i.e. DE, MD, Eastern PA, South NJ...