After Darrell's recent mishap with the driveshaft, I decided to remove the driveshaft from my RS, check it for wear, and re-lube the splines. The procedure is pretty simple: remove the silencer, remove the rear wheel, remove the rear wheel speed sensor, plug the resulting hole in the final drive housing so the oil doesn't leak out (a step the Haynes manual neglects to mention), remove the rear bolt from the paralever, allow the final drive housing to pivot down exposing the rear end of the driveshaft, lever the front end of the driveshaft off the gearbox output shaft, clean everything, lube the splines with Castrol Optimol TA Paste, put it all back together. How long could it really take; a couple of hours at most, right?
When I got to the bit about "allow the final drive housing to pivot down", it didn't. The rear end of the driveshaft is seized fast to the final drive input shaft. No amount of "coaxing" has persuaded it to move so far. The rubber gaitors are supposed to be sealed with a bead of water proof grease, but on my bike the grease is only on one end of the rear gaitor and goes less than half way around on that end. There is none on the other end. I've never ridden a water crossing, and I never use a pressure washer. And yet, having pulled back the rubber gaitor, I can see there is about 1/2 inch of dirty yellow water sitting in the bottom of the swing arm.
Plan B: remove the final drive completely and pull the driveshaft out of the swingarm while it is still attached to the final drive. Except, I think the front end of the driveshaft might also be seized onto the gearbox output shaft. Both the Haynes and BMW manuals say "use a suitable tool to lever the driveshaft off the gearbox output shaft", or words to that effect. No amount of levering with a pry-bar will budge it. The gearbox output shaft and final drive input shaft should be able to slide in and out of their respective ends of the driveshaft and the suspension compresses and decompresses. If both ends are seized, what is providing that movement? I hate to think (gearbox internals?).
I've sprayed the driveshaft and splines as best I can with penetrating oil and am leaving it to soak in overnight. We'll see what tomorrow brings!
If this is the state of the driveshaft of a 3 year-old RS with 22,000 miles, what must be the condition of the average GS after a few years of off-road adventures including water crossings?
Has anyone else had a similar issue? If so, any helpful advice would be appreciated.

Mike - great post albeit of a bad situation, which I hope will be resolved tomorrow. You beat me to the punch as I was going to do the same inspection on my bike following Darrell's experience. Based on my recollection of the Haynes instructions you did exactly what I would have done, so I was reading your post very carefully to see what I could learn.

Could you please take some photos to augment your thread? I do hope that these splines come loose since you need to get the driveshaft out in order to inspect the universal joints, and then re-grease the splines before reassembly.

I am also surprised to read that your rubber gaitors were not properly sealed all around and that there was water ingress into the shaft housing, likely leading to the rust in way of the splines. So the weak link to all of this is the single bead of waterproof grease! I am not going to comment on what I think of that design option, especially in way of a flexible joint that is constantly trying to separate the rubber from the metal.

That Castrol Optimol TA Paste does say that it "Protects highly stressed sliding surfaces from wear and fretting corrosion." So it is pretty important stuff that needs to stay on place.

Reading what you are experiencing just checking the drive shaft makes me think maybe when I buy the next BMW drive shaft bike I’ll have the dealer check the drive shaft before giving them the final payment OR ask them for a free unlimited mileage/warranty on the drive shaft and all surrounding parts. Can’t offer you any suggestion on getting yours apart but with the total failure I experienced and the difficulty checking yours maybe others should check theirs before reach 80,000 miles like my original thought was.

I performed the same general procedure on my 2015 R1200RT when the bike had roughly 30,000 miles on it.

If you look at a parts fiche for the R1200RS you will see there is a snap ring "holding" the shaft in place on both the part of the shaft that is closest to the trans and the part of the shaft closest to the rear end.

My memory of the process I used is foggy at best but I as I recall a fair amount of pressure was required to pop the shaft out of both the rear snap ring and the front snap ring. When I had reassembled everything popping the drive shaft "back in" was a similar process but not easy to do. As noted below I referenced advrider for the procedure and also referred to the maintenance CD from BMW for the RS.

The information and pictures that individuals had posted on advrider relative to the procedure they had used was very helpful.

Hope this is of some help Michael. Good luck

Thanks for the additional comments about this issue, Mike. I was convincing myself that I would never reach the kind of miles (like Darrell) to warrant this procedure. I now have a PM project to take care of.

(12-26-2019, 09:46 PM)mspratz Wrote: Has anyone else had a similar issue? If so, any helpful advice would be appreciated.

I've seen a couple reports where people had trouble tilting back the final drive.
This was back when you had to drop the final drive to change the final drive oil.
Sometimes they only had to walk away and try later.
You mention the Castrol paste. That's what I used on our K1300Ss but I think BMW has moved on to another paste.
When I do ours I'm temped to use the Castrol again since I have it.
I need to order the white sealing grease before I do ours.

On the K1300S I did not remove the shaft. I was able to slide it part way back enough without popping it loose from the snap ring.





   

I was going to post about the snap ring thing, but Olgry1 beat me to it. I pulled apart my 1100RS and also a 1200R years back and do recall the snap ring. The way to beat these things is with some impact, rather than a steady pressure. That will help the snap ring to bounce out of its' groove. But if you're rusted together, it's gonna be tough. Would like to see the pics, as I now have decided to check my bike before the next riding season.

(12-27-2019, 06:51 AM)Olgry1 Wrote: If you look at a parts fiche for the R1200RS you will see there is a snap ring "holding" the shaft in place on both the part of the shaft that is closest to the trans and the part of the shaft closest to the rear end.

The above had me go and check since my Haynes manual makes no mention of a rear snap ring, only one at the gearbox end. Looks like there is only one we have to worry about. That must mean that it is rust at that rear end is giving Michael grief.

   

(12-27-2019, 10:10 AM)Grumpy Goat Wrote: The above had me go and check since my Haynes manual makes no mention of a rear snap ring, only one at the gearbox end. Looks like there is only one we have to worry about. That must mean that it is rust at that rear end is giving Michael grief.

The snap ring is only at the front.
As I mentioned above sometimes the final drive sticks when you try to tilt it back.

(12-27-2019, 10:37 AM)Lee Wrote: The snap ring is only at the front.
As I mentioned above sometimes the final drive sticks when you try to tilt it back.

Also, I would imagine the tilting action on the final drive as it tries to pull off the straight splined end of the driveshaft will add to the rust-induced resistance, since the tendency is to "bend" the splined end of the driveshaft.

Knowing that there is no snap ring at the rear end, a good tap with a mallet should do the trick, I would think.

(12-27-2019, 11:13 AM)Grumpy Goat Wrote: Also, I would imagine the tilting action on the final drive as it tries to pull off the straight splined end of the driveshaft will add to the rust-induced resistance, since the tendency is to "bend" the splined end of the driveshaft.

That's correct. Even with lube on the splines they can stick because of the tilting action.

I stand corrected.

(12-26-2019, 09:46 PM)mspratz Wrote: I've never ridden a water crossing, and I never use a pressure washer. And yet, having pulled back the rubber gaitor, I can see there is about 1/2 inch of dirty yellow water sitting in the bottom of the swing arm.

I don't think water crossings are causing problems for people with rusty splines. Most of us wont ride through water deep enough to submerge the rear swingarm boot.
I think this current generation of boot does not seal as well as previous versions.
Water could be seeping in while riding in rain or the bike sitting out all night in a heavy rain.

Any luck getting the final drive separated from the driveshaft.

Thanks for all the tips and advice guys. I also concluded there is a snap-ring only at the front, which means the rear is seized. I had no further luck after leaving it to soak in penetrating oil overnight. I found the pertinent thread on Advrider.com. There are 53 pages of it, consisting of over a thousand posts, mine now being the last one.
The last couple of pages of the threads are from someone with the same problem I have, final drive seized to the driveshaft, although the amount of rust on mine is way less than his. As Jim Von Barden (the thread originator) points out, if the rear spline is seized, the front one must slide in and out with the rear suspension movement, which means the inner snapring, which is supposed to hold the front of the driveshaft to the gearbox output shaft, is being worked over severely and may be mangled. This might explain why I can't get the shaft to come off the gearbox output shaft.
I gave up, put everything back together, and called the dealer and explained the situation. He gave me a rough quote of $110 to $300 to service the driveshaft, which includes: remove it completely, re-lube both sets of splines, reassemble with plenty of sealant on the boots. He seemed very skeptical of the shaft being seized on the final drive input shaft, like he'd never heard of that happening. I rode the bike out there yesterday. They haven't started working on it yet, and won't until later this week. I asked if this would be covered under warranty, since the problem has obviously existed since way before the warranty expired. He said he'd see what he could do.
In the meantime, I'm worrying that the gearbox output shaft may be severely damaged and need replacing, which means replacing the gearbox internals (thanks BMW). Then I'm up for all the same stuff as Darrell had on his bike when the front universal joint exploded.
Sorry, I did not take any pictures except this one of the dirty water I pumped out of the bottom of the swingarm:
   

Thanks for the update.
Good to hear you were able to get it back together and ride to the dealer.

(12-29-2019, 01:39 PM)Lee Wrote: Thanks for the update.
Good to hear you were able to get it back together and ride to the dealer.

Agree with Lee on this, and his earlier guess that the water in the driveshaft housing is likely not from water crossings but from normal use and rigin in rain etc.

I also read that condensation in the driveshaft housing also occurs with normal use. So some light rust is to be expected, I guess.

Mike - I do hope that your transmission output splines are not damaged beyond use and that the expense is not similar to Darrell's.

I did not look up Jim Von Baden's thread.
I remember on the K1300S you could move the driveshaft back and forth without popping it loose from the snap ring. The R1200 is probably the same.
Maybe with the limited suspension travel of the RS compared to the GS/GSA the front splines will not be damaged.

Reading that ADVRider thread ... lost of good snippets in there.

One thing I was thinking about (and just read someone have the same idea) is to lube the final drive splines every 12k miles when the final drive oil is changed, and also inspect the rear U-joint as well. If this is kept up then any 12k worth of rust should not cause a total seize-up as on Mike's RS. Not having done this myself but having watched several videos since Darrell's and Mike's experiences, It would be a good idea to also inspect the front splines as well.

I have a FD oil change coming in less than 4k miles when I hit 48k on my bike and I just ordered the Castrol molybdenum disulphide paste and a bottle of silicone paste with a nifty applicator brush.

   

(12-29-2019, 04:30 PM)Lee Wrote: I did not look up Jim Von Baden's thread.
I remember on the K1300S you could move the driveshaft back and forth without popping it loose from the snap ring. The R1200 is probably the same.
Maybe with the limited suspension travel of the RS compared to the GS/GSA the front splines will not be damaged.

That would be my hope. The reason for the paralever is to try and keep the radial length and angle constant through the arc swing.

Michael, good luck with your driveshaft/splines. I am probably 50 miles from you so if there is anything I can do to help just pm me.