www.boxertrix.com

how dificult is it to change the rear oil seal in the final drive housing????? i mean the small one just under the rubber boot.

if you're on about the one at the front (input) end of the final drive, then you need a special tool - like a big socket but with tangs - to undo the locknut. Mucho tight. Have got tool, live in barnsley. Hang on - I could be thinking about me K - let me check...

Yeah that's right...a special castle nut tool required. Best done with an air gun....very tight.
The seal that BMW supply is crap. replace it with a double lipped variety. Much bettter!
Bailey.

yep, it was the r - 4 years ago at 25000 miles, and it's 4 tangs not two. The bearing was fine - it was just a crummy seal that wore out at 5 years old.

If your replacing the seal, also replace the metal collar/sleeve that fits inside the seal.

thanks guy's but are we on about the seal in the final drive where the wheel fits. the small seal just behind the rubber bellows.

renagade wrote:thanks guy's but are we on about the seal in the final drive where the wheel fits. the small seal just behind the rubber bellows.

make your mind up - the seal in the final drive where the wheel fits, isn't small, and it isn't behind the rubber bellows.

You have a large seal "where the wheel fits" = the output flange seal.

And a small seal "behind the rubber bellows" = the input shaft seal.

The large output flange seal is a 5 minute job.

The input shaft seal is a bit more involved, and requires an airgun toundo the shaftnut, and a special 4 pronged tool, to undo the castellated insert in the input tunnel. And if your doing this seal, also replace the small metal collar that slides inside the seal (cost about £3), not just the seal.

I had the same issue with a leak, removed the shaft-drive housing and later found out the difficulty in dismantling it (specialist tools required). The bearing left good, just the leak!

After talking with Darren at motorworks I decided to leave it. He suggested it was a build-up of oil within the boot as these are prone to leaking a bit of oil from the INPUT seal (see B below). On inspection when I had cleaned off the oil the seal looked OK, not able to really check it as I did not have it completely appart. But the pivot roller bearings (see A below) were shot and I was glad to be able to replace them.

Anyhow, Darren suggested/recommended putting on some good clips on the boot to stop any oil coming out, and empty it every few thousand miles. Only done 200 miles since I did it so can not really comment yet. But no leaks so far with the decent clips holding the boot on

Of course it could be the gearbox output shaft oil seal that has failed, leading to oil leaking out of the 'box and down the inside of the arm to pool at the bottom of the arm and in the rubber boot.

This is a much easier fix and can be fairly well diagosed by checking how much oil is inside the arm and how far up it extends. A bit of misting or spray from the bevel box input seal failure should not extend that far or be as noticeable (typically).

When mine showed sign of leakage it was from the Bevel box I got it replaced by a specialist (small company of bike engineers that had previously worked for the local BMW dealer) as when they took the seal out they found the reason for its failure was a failure of the double bearing on the input to the bevel box

http://www.maxbmwmotorcycles.com/fiche/ ... d=12082016 (section 33)

so replacing the seal would have been a waste of time. The old bearing had to be pressed out with a hydraulic press

Hi folks, does this fit in with my query viewtopic.php?f=4&t=22535 ?