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Old 07-06-2012, 07:17 AM   #1
manfromthestix OP
Lost in Space
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Joined: Dec 2004
Location: Lexington, Virginia
Oddometer: 2,313
Final Drive Crown Seal replacement project

Several years ago I was just a couple of days away from leaving on a three week tour of the Canadian Rockies when I noticed that the final drive crown seal on my R1100RT was leaking. I had never done any maintenance of the FD except oil changes, the long trip was looming in three days, so of course I panicked and headed for the nearest dealership to get it repaired properly, cost be damned! I lived in central Wyoming at the time so that effort entailed loading the bike in my truck, driving 300 miles to Salt Lake City (excellent shop, BTW), spending most of a day at the dealership, and driving 300 miles home. The total bill was 1.5 days of my life burned up, shop costs of $240, and the cost of the drive . Ouch. But the seal on the RT made it through the trip and hasn't failed again to date.

Fast forward to a few weeks ago and I noticed the FD crown seal on my 1150GS was leaking. BTW, I have 50,000 miles on the bike and it has been literally flawless in every respect even though I ride it pretty hard and do quite a bit of gravel roads and ratty asphalt, two-up and loaded like a moving van. This time around I wasn't under any time constraints so I thought I'd just do it myself. First step was to peruse ADVRider for guidance, of course, and I found several references to how easy this procedure is but didn't find a photo-documented guide. I've been doing all the work on my BMWs for about 10 years now so I feel more confident and thought WTF, I'll just try this. I ordered the proper seal and a crush washer set from Bob's BMW and had it in my hot little hands in less than 24 hours for about $40 including shipping. Bob's is outstanding, thanks for your help, Matt!

So here we go. Here's the rear wheel, you can see oil all over the paralever and rim:

Wheel off, yup, we got a problem here:

Clean it up good with some nasty chemicals, shop towels, compressed air, and elbow grease:

I'm working out in the driveway because it's so ferking HOT and something literally crawled in my garage and died, so it stinks horribly in there. Better hurry, storm's a-comin'!

Put a couple of the wheel bolts back in and wobble them at 9 and 3, 6 and 12 o'clock to check for play, none detected:

Use a drill driver to carefully screw in some self-tapping sheet metal screws; not too deep, only until they bite good, not so deep that they hit the bearing behind the seal:

Grab with a pair of pliers and carefully pull/pry the old seal out (it's EASY). BTW, I drained the old oil into a clear pop bottle so I could look at it and check for discoloration and metal flakes; all was good and no flakes on the magnetic drain plug:

Check out the bearing, clean out and bits of rubber and crap introduced by pulling the old seal out, inspect bearings (they looked flawless):

Smear a thin film of oil on the inner lips of the new seal (not the outer edge) and CAREFULLY tap it into place, making sure you get it square and don't tap it in too deep (it should be flush with the housing, like the old one). It goes in pretty easy:

Insert drain plug with new crush washer, fill with new oil (I used Mobil 1 synthetic gear oil of the proper weight), put the fill plug with new crush washer back in, spin the hub around a little to see that everything is working as it should, reinstall the wheel, clean up, wheel the bike in the garage about three minutes ahead of the deluge:

Once the rain stopped I rode the bike about five miles and rechecked the oil level, but it was fine (to the bottom of the threads) and I haven't seen a drop of oil leaking from the new seal in the 500 miles I've ridden since the replacement.

This was the easiest repair/service I have ever done on a BMW and it took less than 45 minutes from start to finish. I did not have to remove the FD unit from the bike and did not have to crack open the case to get it done. I feel like an idiot for all the time, effort, and money I spent getting this done on my RT by the BMW shop.

I hope this is of some help to a few people! Ride, ride, ride!

"If it doesn't blow smoke and make noise, it isn't a sport!" - radio ad for shop in Bozeman, MT
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