K11 Owners Group

Grunter · Posted: Sun Oct 23, 2022 4:52 pm Post subject: Final drive start of an oil leak.

I have found that I have a slight oil leak from the final drive on my K1100LT. Using the workshop ROM Disc, I can see where the seal should be but cannot make head nor tail how to replace it. Any clues please. As the drive box has to come off would it be worthwhile replacing the rubber boot as well.

When I say it has a slight leak, there is an escape of oil but the level has not visibly dropped in 2500 miles since it was changed.
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1997 K1100LT
1994 R1100RS

Mike d · Posted: Mon Oct 24, 2022 4:12 pm Post subject:

Hi John,

Which seal are you referring to.

Mike

Grunter · Posted: Mon Oct 24, 2022 4:46 pm Post subject:

The one I think will be the problem is the one that stops the oil from escaping from the final drive into the casing where the drive shaft splines connect to the input shaft.
There is one listed in Motorworks new parts list but I cannot see where it is located on the exploded diagramme.

When I owned my K75 and K100 bikes that seal always leaked slightly but the sealant between the swinging arm and the final drive housing ensured there was no leak between the joint.
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1997 K1100LT
1994 R1100RS

Flying Duck · Posted: Mon Oct 24, 2022 6:28 pm Post subject:

I think #4 here:

https://www.realoem.com/bmw/enUS/showparts?id=0536-USA-09-1992-89V2-BMW-K_1100_LT_0526,_0536_&diagId=33_0638
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93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
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14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

Grunter · Posted: Tue Oct 25, 2022 4:37 am Post subject:

Mike d · Posted: Tue Oct 25, 2022 1:35 pm Post subject:

Yes, in the BMW Club Uk tool Hire facility we have the castellated tool for the threaded ring, as well as the drift for installing the new seal in it (but you could get away without that.

A little sealant on the threads of the ring will prevent any oil wicking up the threads.

Mike

Flying Duck · Posted: Tue Oct 25, 2022 3:15 pm Post subject:

Grunter · Posted: Tue Nov 08, 2022 7:19 pm Post subject: Final Drive

I have pulled the final drive off the swinging arm after draining the oil. There was about a large spoonful sitting in the bottom of the rubber boot, perhaps 20-25cc's, The driveshaft was clean and dry internally so the oil had not migrated down from the gearbox seal.

The oil I used is a relatively new semisynthetic 75/90 GL5 which is virtually colourless and had been used for around 2500 miles. It was still very clean but with black streaks which I assume was the seal in question starting to break up.

What I did find was the input shaft was able to be moved in and out by hand around 5-7mm. Is this normal? (Not backlash when turned, that is fine).

The needle bearings were good and there were no rough spots on the splines which were perfect and appeared unworn. They needed greasing though!

I don't have the expertise to change the seal so it is being done for me by an independent dealer who specialises in BMW's
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1997 K1100LT
1994 R1100RS