R12RT Rear Drive Unit Failure!!

[roborider]

I make this post for two reasons. One, to see if anyone else has had this problem (on any model) and, two, to warn you about a possible safety concern.

My 05 R12RT (18k miles) had the press fit hub on the rear come loose from the drive unit. This caused the wheel to wobble, thus damaging the disk and brake caliper. Of course, if the wheel had come off, that would have been bad! BMW uses a safety ring to keep the hub on, but obviously the hub is not supposed to come loose from the drive axle. It is heated and press fit onto the splined axle.

The dealer and BMW fixed it under warranty, and fast, so no complaints here. They stood behind the warranty as expected. The replaced the drive unit and hub, brake rotor, and caliper and pads.

As a warning, make sure to check your rear wheel as part of your pre-ride inspection. Put it on the center stand and give it a wiggle. Mine would wobble about 1/2. It behaved just like the lug nuts were loose. I also notice that there was play in the splines now that it was fixed. I thought this was play in the drive shaft. When you would apply throttle after coasting, there was a bit of a lurch. The bike is like new now.

Anyone else had or heard of this before?

Again, my thanks to BMW and the dealer in Raleigh for the excellent and prompt repair.

Robo

 

[cjack]

I make this post for two reasons. One, to see if anyone else has had this problem (on any model) and, two, to warn you about a possible safety concern.

My 05 R12RT (18k miles) had the press fit hub on the rear come loose from the drive unit. This caused the wheel to wobble, thus damaging the disk and brake caliper. Of course, if the wheel had come off, that would have been bad! BMW uses a safety ring to keep the hub on, but obviously the hub is not supposed to come loose from the drive axle. It is heated and press fit onto the splined axle.

The dealer and BMW fixed it under warranty, and fast, so no complaints here. They stood behind the warranty as expected. The replaced the drive unit and hub, brake rotor, and caliper and pads.

As a warning, make sure to check your rear wheel as part of your pre-ride inspection. Put it on the center stand and give it a wiggle. Mine would wobble about 1/2. It behaved just like the lug nuts were loose. I also notice that there was play in the splines now that it was fixed. I thought this was play in the drive shaft. When you would apply throttle after coasting, there was a bit of a lurch. The bike is like new now.

Anyone else had or heard of this before?

Again, my thanks to BMW and the dealer in Raleigh for the excellent and prompt repair.

Robo

I've heard of it. Someone on another forum (?) posted a picture of how he implimented a preventitive measure. It was some kind of bolt thru the hole with washers on both sides. Looks better than my description, but essentially that was what it was.

 

[grasslander]

I have posted this on the BMW xplor site....

My 2005 R1200ST just had this happen. My ST has 15700 miles on the clock. I found the wobble on a pre-ride inspection. I know of one other individual from Canada that had this happen. His entire final drive was replaced due to the spline being loose. i understand that at one time there was a Service Information Bulletin for this happening on early R12GS machines. Again recommending complete FD replacement for loose splines.

BMW has now changed the approach. They have instructed the dealer to purchase a special tool required to re-machine the axle spline and fit a new splined wheel adapter. I don't know if I care for this approach. If it loosens again can it be re-machined again or will I be stuck with an out of warranty FD replacement? I don't know if BMW needs to replace the entire FD. I'd sure feel alot better if they replaced the axle tube and adapter as a set vs a field dressing of the old axle tube. But maybe the axle tube can't be replaced and it does require the complete drive be replaced to replace the axle tube. Has BMW decided to attempt to save a few bucks for a quality flaw and leave it for me to sort out the bigger expense later? I guess i have another 20000 miles to test this for BMW.

Bummed and definitely not feeling good about the warranty approach I'm getting. It would be nice if someone at BMW could explain this one to me.

 

[marcopolo]

I had this exact failure this past July while in Wyoming on a long road trip. I took the bike (2006 R12RT) to Salt Lake City and the dealer there replaced, under warranty, the Final Drive (complete with flange), the rotor and all wheel nuts. Before leaving for Salt Lake, a friend had e-mailed me the 2005 BMW USA service bulletin which said quite explicitly that the entire FD had to be replaced, not just the flange, because the splined axle tube would most likely have also suffered damage and not just the splines on the flange. That would suggest the only way to get a new axle tube is to replace the Final Drive.

Grasslander, has BMW USA issued a new service bulletin? I can't believe they could fix it quite that easily, especially when you read the 2005 service bulletin. If that's the "new" solution, how did RoboRider get his FD replaced under warranty for the same spline problem?

BTW, I have copied that 2005 service bulletin verbatim on the long thread dealing with Final Drive Viscosity here in Hexheads. You may want to have a look at that bulletin, and ask your dealer why BMW has very recently replaced FDs under warranty for the exact same failure. If you want me to copy it again here, just shout.

Good luck.

 

[professor]

There is a good article on final drive failure in the new Owner's News.

 

[grasslander]

Grasslander, has BMW USA issued a new service bulletin? I can't believe they could fix it quite that easily, especially when you read the 2005 service bulletin. If that's the "new" solution, how did RoboRider get his FD replaced under warranty for the same spline problem?

Evidently there is...
I discussed this with the dealer tech on Tuesday. He told me that when he input the spline failure on the BMW system, the system gave him specific instructions on how to proceed.

Step 1:
BMW required him to attempt the adapter replacement using a "special" BMW tool to heat and remove and heat the adapter and press it on the axle spline.

Step 2:
If the play was no longer present, job done.
If play could still be determined, FD replacement was then approved.

The tech says BMW has explained that the the axle tube is steel and the adapter is an alloy. It is usually the alloy adapter flange that is the wear item. I'm out of town and he was going to take a digital photo of the axle tube spline for me prior to new adapter install.

I got a call today that the alloy adapter was installed and no play was found. I'll check it out next week when I return to Kansas.