Murphy Stikes again!! Driveshaft boot R & R tips?

iammemares · iammemares's Garage

Well here we go again. I go out to do a final shake down 10 days before a major 2 week trip and come across a rip in the rear U joint Gator. So tonight I started the tear down process. I have never done this ( R & R) the driveshaft before and would REALLY appreciate any hints.

My basic plan: after basic teardown,

Heat up and remove rear pivot bolts
Carefully remove Rear joint from DS
Remove U Joint
R & R Gator
Loosen and remove RR shock lower bolt
Heat and remove front pivot bolts
Carefully remove Swingarm
Remove FR U joint
R & R front boot (figure I may as well while I am here)
Lube tranny side splines and pivot bearings (is BMW # 10 best for this?)
Reinstall Front U-Joint
Reinstall swing arm apply loctite and torque pivot bolts
lube rear splines and pivot bearings
reinstall rear U joint and install onto DS
Loctite and torque rear pivots
Final reassembly

Any Tips or Tricks, things to watch for or other things that may need attention while I am in there is very appreciated. Bike is a 95 R11RSL with @ 27K on it Need to buy parts and finish by this weekend.

Thank you very much, Mark

roger albert · 06-17-2003, 05:04 AM

Sounds about right. Be ready to replace rear pivot bearings as necessary (though RSs seem to need that less often)

good luck

sud-z · 06-17-2003, 05:06 AM

I recently swapped out a gearbox on my 96 R1100RSL. Shouldn't be too bad if all you have to remove is the swing-arm and drive shaft. Wouldn't hurn to have a haynes or shop manual around though.

As far a grease, not sure about the #, but its the red stuff.
Have something handy to support the final drive when you remove the shock and torque arm. Just hang the brake caliper out of the way. Don't bother draining it. Check the ABS sensor gap (if applicable) before you remove the brake. Mine was way tight. Beer can shims work great.

The biggest pain in the arse by far was getting the pivot bolts out. 12mm hex key I believe. I had a hard time finding one. The thread lock they use is VERY strong. I did not have a heat gun. Instead I inserted the hex key in the bolt, and used a propane torch to heat the hex key. Took some time, but it worked. Just be patient. The last thing you want to do before your trip is to back out the bolts, leaving the threads in the swing arm. It can happen. I used the blue loc-tite 242 on reassembly. Maybe it won't be so hard to remove next time.

Good luck. Have a nice trip. Hope this helps.

Sud-z

DavidSoine · 06-17-2003, 05:23 AM

Index the U-joints properly. Not mentioned anywhere in the service documentation.

best,

Dave

iammemares · iammemares's Garage

Great info, keep it coming. David, you mention indexing the U joints and I agree that it is not mentioned in the technical instructions. To what are you refering? What is the proper indexing procedure?

Thanks again to all, Mark

DavidSoine · 06-17-2003, 06:43 AM

I'm trying to think of a good way to explain this. To cancel as much vibration as possible, we want the yokes on either end of the driveshaft to be in the same direction, not at some other angle. It is easiest to think of a (Rear wheel drive) car driveshaft.

Let's try it with ASCII art, here is an attempt at a side view of a driveshaft with U-joints attached:

Correct indexing:

-- +)------------(+ --

Incorrect (90 degrees out of phase):

-- +)----------- +)--

If someone has a better explanation, please let's have it.

Dave

roger albert · 06-17-2003, 07:56 AM

I think that's a pretty good attempt, but have to admit to not understanding it, so that means my opinion here is worth squat.
I don't see a clear interplay between the front and rear rotating masses, despite them being physically connected.

Was there a service bulletin on this? I've never seen it as an issue on cars, but the relatively long longitudinal shafts minimize angularity (which has to be involved, otherwise they're just two independent masses) I could buy that, but I've never seen it as an issue on indepenent suspension halve shafts either, and they are much like our bikes, angle wise. I think the CV joints (instead of Ujoints) remove that as a concern, but I wouldn't swear to this.

Where did all this indexing spring from? What's the technical source.
I'd like to learn more. I know I've ignored the indexing for years and dozens and have never had an issue. At most, incorrect indexing allows another problem to show up. It's not an all/nothing problem.

curiously yours
roger

DavidSoine · 06-17-2003, 08:56 AM

If the shafts on either side of the U-joint are at an angle, their angular velocity is not the same - one shaft will speed up then slow down (twice per rev) relative to the other.

If the shaft has a u-joint at each end, the velocity variation can be cancelled out by indexing the U-joint, if the U-joint angles are "equal and opposite" - similar to the situation on the base R11S (short shock/long arm).

"constant velocity" joints do not have this velocity variation problem - which is why they are used in situations where the angles between shafts are great (esp. front wheel drive).

best.

Dave

Dave Hopkins · 06-17-2003, 11:54 AM

In car & truck driveshafts they make a big deal out of indexing them properly and the same issues should apply here, yet BMW is silent on the issue? I read a brochure years ago published by Spicer Dana corp on the subject, have a good understanding but it is about velocity fluctuations, when the driveline is opporating at an angle its speed is not steady, so the rear U joint needs to be in time with the front and as near as possable to equal and oposite direstions.
Roger, do you prefer to assemble
1: The driveline in the housing rear pivot first, then slide the assembly on the bike? OR
2: Put the front half of the shaft on the bike, the swingarm/driveline housing, then assemble the rear pivot.
I have done plan 2 twice and it is a huge pain in the a--, I think plan 1 is the prefered way?