2014 R1200GS WetHead Final Drive Boot Damage/Failure

[Boxflyer]

A week ago while riding with a buddy that owns a 2014 R1200GS, we had parked for the night and I happened to notice that the rubber boot between the Final Drive and the Paralever was not completely seated at the top where it joins the Paralever.
Later in the week, I was doing a 12k service on this bike, so I could address the final drive boot sealing issue.

What I discovered was that because the front/top of the boot clips were not properly engaged, the accordion pleats on the boot had been worn thru due to contact with the U-joint yoke on the driveshaft.
So, because the front of the boot had been displaced rearward, the collapsed boot was ruined and was also letting in water/debris while riding in addition to the poor seal at the front.

I have a couple of extra final drives, complete with paralevers, for the WetHead and was able to cannibalize a rubber boot from one of those to complete the 12k service.

This is the part number for the replacement final drive rear rubber boot. 33357708117 https://parts.maxbmw.com/p/BMW__/Rubber-boot/46939180/33357708117.html

And as we all know, posts without pictures are incomplete...

Rubber boot in its normal/resting position. Angle is about 45deg, and folds on the boot clear the rear U-joint yoke

Rubber boot in approximate position if the front/top clips and seal are not properly seated in the Paralever

Here I'm trying to show how the inside of the folds of the rubber boot are compressed when the front of the boot is pushed reward.

This is the hole worn in the rubber boot after contact with the rear yoke on the U-joint.

Just another point of reference to pay attention to when performing routine maintenance on these bikes.
Hope this helps someone.

 

[cap]

Nice pics. And as an aside, there is very little residual Staburags NBU30 in evidence around the circumference of those boots. In my experience, if you apply a liberal amount of the goo around the boot, it seals well. And the next time you remove the boot for inspection, you will need to wipe off the now-dried up remnants from your prior application, from both ends of the boot, and the swingarm, and the final drive. And after wiping off the crusty Staburags remnants, you will still have a moist and tacky bit left on the boot. So, if you pull your boot, and you don't see a continuous smear of Staburags around the circumference of each end, then it wasn't applied properly (or at all?).

On my 2 wetheads, the boots weren't well-sealed from the factory, and both had rust developing on the final drive spline. Based on the pics above, it would seem that improper sealing is a common problem. On my 2019 RT, the final drive is rusted so badly that I can't separate it from the driveshaft with only 8000 miles of use. On my 2017, it was mildly rusted at 9k miles, and with some persuasion it was separated. On that bike, with proper sealing and lubrication, there have been no more problems in another 20k miles, checking every 6k miles.

Cap

 

[pglaves]

Nice pics. And as an aside, there is very little residual Staburags NBU30 in evidence around the circumference of those boots. In my experience, if you apply a liberal amount of the goo around the boot, it seals well. And the next time you remove the boot for inspection, you will need to wipe off the now-dried up remnants from your prior application, from both ends of the boot, and the swingarm, and the final drive.
Cap

I would prefer to use a lubricant/sealant that didn't have "dried up remnants". What are people using besides the Staburags goop??

 

[Boxflyer]

I'm usually an advocate of following Mfgr's specifications for lubricants, sealants, torque, and procedures...BUT...

I have done about 50-60 12k services on this WetHead series of bike, (I'm making no comment about anything else since I've never owned a K75) and have found the OEM recommendation for spline lube and FD boot sealant to be lacking.

What I have switched to that DOES work very well is Honda M77 lube for the splines and White Lithium grease for the boot seals.

https://www.amazon.com/Honda-HN-08798-9010-MOLY-PASTE/dp/B0083BWUYW
https://www.amazon.com/Lucas-Oil-10533-Lithium-Grease/dp/B004X70LZA/ref=sr_1_5?crid=3Q9E2RYNPNB4B&dchild=1&keywords=white+lithium+grease&qid=1594755906&sprefix=white+lith%2Caps%2C171&sr=8-5

 

[Omega Man]

Another great job

Thanks for the effort!

I will add it to the index-

https://forums.bmwmoa.org/showthread.php?70623-Wetheads-Accessories-Mods-and-DIY-s

OM

 

[52184]

Staburags NM 30 contains barium, which is supposed to be a water repellent. On one bike I have used a thick silicone brake grease and on the other a very sticky NGL2 gear grease. Time will tell if either works as well or better than the Staburags. IIRC BMW also packs Staburags between the swingarm and frame on some bikes, the K1300GT being one example. I haven’t settled on anything yet to replace that application but will try the tacky NGL2 grease next time I pull the swingarm.

Best,
DeVern

Best,
DeVern

 

[lkraus]

I would prefer to use a lubricant/sealant that didn't have "dried up remnants". What are people using besides the Staburags goop??

Sil-Glyde

Packaging varies, sometimes labelled "Brake Lubricant", other times just "Lubricating Compound", same stuff.

Does not dry out or run, withstands heat, does not damage plastics, rubber, paint.
Works well on sliding brake components and anywhere you might use white lithium grease.

"Sil-Glyde® Lubricating Compound A longer-lasting, high film strength protective lubricant for all surfaces, including: rubber, metal, wood, glass, and plastic. Won’t melt, freeze, gum, or run off. Performs from -20 deg F to +400 deg F. Grease consistency stays put and won’t drip off like silicone oils. Harmless to rubber and car finishes. Suggested applications: Trunk seals, rubber bumpers, speedometer cables, brake parts, window channels, hood strips and pads, rubber gaskets, and belts."
also
"Sil-Glyde® Brake Lubricant is a silicone-based brake lubricant recommended for the entire brake assembly, is compatible with plastic and rubber (EPDM & Nitrile), and dampens vibrations between contact points. It is moisture-proof and heat resistant to over 425 degrees F (218 degrees C), which means it won’t burn-off like other brake noise products. Its long-lasting properties provide a noise-free brake installation and easy disassembly. Using AGS brake lubricant is one of the keys to eliminating disc brake squeal and protecting parts from corrosion and rust."

 

[52184]

Sil-Glyde

Yes, that’s what I’ve used on one bike. I’m about 4K away from 12k service and a good look at how it’s doing.

Best,
DeVern

 

[jandhumphreyme]

I use Molykote 111 O-Ring Grease, made by Dow Corning. Safe for plastics and rubber, won't wash out, resists drying and hardening. Stuff is still grease like after 12k miles when I service the boots.

 

[105258]

Boot Sealer

I would prefer to use a lubricant/sealant that didn't have "dried up remnants". What are people using besides the Staburags goop??

I use a pure silicone grease available almost anywhere. I put lots around the inner seal area just behind he clips and on the mating surface on the drive. It works well and there is always residual amounts on the boot when I check the splines.