R1150RT Rear Drive Leak

[Mr. Frank]

After 24K miles and 15 months my 2004 R1150RT has developed a rear drive leak at the rubber boot. It seems to be coming fron both the front and rear underside of the boot which was fairly wet. A little oil can make a big mess, but the amount lost does not seem great. The drive is full and the wheel is clean.

This is covered by warranty, but I'd like to hear what causes this failure mode, and what is involved in its repair.

[Colt03]

Frank are you using Synthetic in the rear drive ?

When I used synthetic on my K bike I experienced a weeping, when I went back to dino it went away.

I still use synthetic in the tranny just not the rear end.

Good Luck

[JohnV]

Hi Frank,

My 02 R1150RT was weeping from the rear of the rubber boot. It started before I changed to synthetic oil and didn't get any worse after I went to synthetic. I got tired of wiping it off so one day, I removed the boot and there were a few drops of oil in it. I cleaned the boot up real well and put it back on. I didn't even change the tiewraps as they slid off and on easily. That was 10000KM ago and I haven't noticed any leaking since. Give this a try if you already haven't. HTH.:)

John Veilleux
St.Bruno Quebec
Canada

[Mr. Frank]

Originally posted by Colt03
Frank are you using Synthetic in the rear drive ?

When I used synthetic on my K bike I experienced a weeping, when I went back to dino it went away.

I still use synthetic in the tranny just not the rear end.

Good Luck

Hi Craig,
Yes, I'm using Mobil I. My understanding is that modern synthetics do not harm seals. However, once there is a failure, they are more likely to get through. I had a bad leak of synthetic gear lube past the drain plug on a K75 on a trip to Nova Scotia. A new crush washer solved the problem.

This leak is beyond seeping. The underside of the boot is quite wet, and the rear drive housing is pretty messy.

[basketcase]

I'll make you a great deal on a low mileage K11LT! :D

[bmwmick]

Frank,
I'm using Mobil-1 gear lube in all three of my bikes, no leaks!
As far as how they will repair, it depends on which seal is leaking. It sounds from here (about 1,800 miles West of you) :p like the pinion shaft seal is seeping a little OR the transmission output shaft seal is damaged. If you slide the accordian boot back toward the rear, you might be able to determine if the swing arm interior is dry or not. If dry, it's the pinion shaft seal, if wet, it's probably the tranny output shaft seal.

HTH,
Mick

[dzimbric]

I experienced the same thing this year at 26K. The shop replaced it under warranty, seems prettty common, Bradfordbenn had his '02 RT with 6K in for the same repair that week.

Your bike is still under warranty, the shop should replace it at no cost. If you try to do iit yourself it requires a special jig to hold it, a lot of heat to soften the loctite and a bit of cussing.

It will only get worse, get the shop to replace it the next time you get a major service. Eventually it will start making a mess of the rear wheel and final drive assembly.

We did some research several years ago regarding oil seal failure on our gearboxes and found the most common cause was that the polish on the shaft was not smooth enough and the rotating shaft began to eat the seal. I looked at the finish on my final drive and saw a finish that is not mirror smooth like that specified by the seal manufacturers.

[Mr. Frank]

Thanks, dzimbric. Was your problem the pinion gear seal? Have you heard what causes it?

[dzimbric]

Item 4, Shaft Seal, Part Number 00 00 0 451 185

please see the attached link.
http://www.maxbmwmotorcycles.com/fiche/diagrams.asp?mospid=45655&VIN=&hg=33&fg=10&model=R1150RT

Seemed pretty common, the dealer was out of stock as he had replaced several in a short period of time. I would guess it was caused by the surface of the bevel gear shaft, but no one in any official position is saying why they are failing.:dunno