Thu, 08/19/2010 - 10:48
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I have a leaky drive boot on my R50 and need advise on how to replace it. I've actually done it before following advise from an article in BMWMOW magazine, but that was long ago. It seems that I was able to replace it without removing the swing arm pins. Any advise would be greatly appreciated.
Thanks!
Dave
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Thu, 08/19/2010 - 11:51
#2
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My suggestions would be to
My suggestions would be to have another boot available or be able to get one if you end up holing the first. Unless you can stand the downtime.
Another thing is the bolts that hold the driveshaft to the tranny output. When I was restoring my R69S, I found these bolts to have allen heads to them. For the /5 and later bikes, they use a hex head bolt which is perfectly fine for the /2...they're easier to get a wrench on. It's possible to reuse your old bolts but the allen head makes them difficult to use. If you choose to reuse, thread them in by hand into the output flange and ensure that they feed smoothly. If they don't, that means they're stretched and you must replace them.
If you want new ones, get the hex head ones and be sure and get the short ones without the lock washer. The part number should be 26 11 1 242 297...they should be 13mm long. The first series of bolts from BMW were long with lock washer 26 11 1 230 414 (14.5mm long). There's a possibility that the lock washer can fracture, thus leaving the bolt with no tension. It would then be possible for it to back out...not good. BMW put out a service bulletin saying they had tested the shorter bolts (shorter by about the thickness of the lock washer) and they worked fined.
When I put the shorter bolts on my R69S, I installed them clean, dry, with blue Loctite. I used a 12-point 10mm wrench with a rag in my hand and gave it a good grunt. It's impossible to get a torque wrench on these bolts unless you have an adpater and then you have to do all kinds of math to compensate!! The torque is called out as 29 ft-lbs.
Thu, 08/19/2010 - 12:20
#3
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Torque wrench adapter
Cycle Works in Kansas (look them up on the Resource Links page) sells an adapter, and I have it. If you put it on your torque wrench so that it's at 90 degrees to the axis of the wrench when the wrench clicks, then there's no higher math needed.
But Kurt is right about replacing the screws and getting the short ones. I would replace them regardless.
Thu, 08/19/2010 - 12:28
#4
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Darryl -
You're right about
Darryl -
You're right about the 90 degrees, but I didn't want to get into that.
On another forum, I had people tell me all kinds of crazy things about torque wrench extensions. I tried to go through the math on-line to no avail. I even went as far as creating a home experiment with photographs. I used a torque wrench to lift a fixed weight. Then I use a piece of steel as an extension and took new sets of readings. Still didn't help.
Oh well...
Snowbum has a view of an adapter on his website; paragraph #4 about 1/2 way down:
Thu, 08/19/2010 - 15:36
#5
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Kurt, I can't believe you
Kurt, I can't believe you went through all that effort. What do you think about putting those photos to good use by writing an article for the Bulletin? 
I remember again why I can't look at Snowbum's website. I must be epileptic, every time I go to his site I get blurry eyes and a headache. All those font colors, all those background colors, the different sized fonts... I can't focus on what he's actually writing.
Thu, 08/19/2010 - 16:51
#6
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Darryl -Ha! Before I opened
Darryl -
Ha! Before I opened your post, I figured you'd ask me that! Well, I'll have to think about it. For some reason, a bit of the theory/equations didn't match the results. I was trying to do it by myself using the timer setting on my camera. But since I didn't have good metal to work with, there were situations where I couldn't stabilize the setup before the camera snapped. Plus, I'm sure there were frictional aspects that weren't accounted for.
I'll give it some thought...maybe find a better "adapter" and restage the event.
Fri, 08/20/2010 - 09:57
#7
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Getting the boot
Thanks for the information everyone.
I'm not sure that I'm doing this correctly, so I hope those of you who replied to my question will see this.
I will remove the rear wheel because I also need to replace the tire and I also bought the improved brake shoe lining that I want to install. Three birds with one stone.
Thanks again,
Dave
It is possible to replace the boot without doing anything more than removing (and replacing) the 4 screws that hold the driveshaft to the transmission output flange. There is >just!< enough space available to do it. But you must be extremely patient, have good hand strength and you will certainly increase your vocabulary, especially if you make the mistake of trying to help the boot along with a screwdriver and put a hole into it. DAMHIK.
You can get a bit more room by also removing the rear wheel and then the final drive. This is probably a worthwhile thing to do, especially if you've got any impatience in you at all.
Good luck, and be SURE to orient the boot correctly so you don't have to remove it and reinstall it the other way round. DAMHIK.
VBMWMO Webmaster,--Darryl Richman
Rider #52 in the 2012 Cannonball--follow my blog!
http://darryl.crafty-fox.com