Hi Guys, haven't been keeping track of what's going on. For that, I apologise. Just noticed Inge is no longer with us. My RT has been running well and still fun to ride. However, just noticed a small oil leak from the Final drive, appears to be the output seal. Are there any tips & tricks to replace this. Any suggestions would be greatly appreciated.

lots of posts about this throughout the forum

yes, it is relatively easy to do , if you have some mechanical skills
however there are warnings about replacing the case seal as well , and caution with splitting the bevel box halves ...ie the bolts and tools for the process

there are a few alternate seals available ...but resurfacing the axle part - hub is recommended  if fitting any new seal to rotating metal shaft ..(eliminates the sharp edge of the old running - mating surface at the seal edge interface )

good luck !

Have you checked for any play in the wheel. Sometimes as the bearing begins to fail, you get oil weeping passed the seal. 

If the bearing is o.k. then replacing the seal is easy enough.

Mike

Charlie, got me thinking... Hard to tell if it is actually the output seal or the case seal. I have no oil on the disk and when i'm wiping it of i can't really tell if it comes from the bevel box halves. i know for sure it is not the drain plug. I suppose the only way i can be certain is by taking the disk off. 
How much of a drama is it to do the case seal? Once pulled apart i'll have to do both anyhow.

Unless it's been removed before taking the rear disk off can be difficult and often requires drilling the bolt heads off due the uber threadlocker BMW used at the factory as well as time.

The main seal ans O-ring between the halves is easy as Duck says the allen head countersunk screws can be difficult. I put the key in the hex and hold some tension then apply heat, they usually come out as the heat melts the red loctite. Don't just try to undo them without the heat unless you know for sure they have been out before and will come easily.

And when you reinstall the rear disk I always use anti-seize instead of thread locker in case I ever need to remove it in the future. My guess is that the BMW engineers spec'd threadlocker to be extra safe on brakes but since the lug bolts that also hold the wheel on also hold the rear rotor on I think it's overkill.

Thanks again for all the helpful tips. All went pretty well, the disc came off quite easily. Indicating it had been off once before. The allen casing screws....hmmm, a little tight. But heating them most certainly did the trick. However, they already looked a bit worn before i got to them. I have put it all back together again and all is well. But i would like to replace them regardless. If i have to pull it apart again in the future, i want to make sure i don't need a drill to do it. 

Where can i buy the right 8 hex bolts? The heads on them look a bit 'lower' than they usually are, since the disk bolts are very close. There isn't a lot of clearance.

This is where I buy most of my bolts etc. https://www.bolt.com.au/