Parts Question

I have a 1980 R100/T bike, I'm currently rebuilding the front forks.

I've got all of the parts I think I need but found one part on the micro-fiche that I just can't figure out where it goes.

See photo item #13. P/N-31 42 1 231 483 Shaft Seal. What shaft?

Any ideas where this o-ring goes? I know it looks like the brake caliber pivot-bolt o-ring, but it's not, different P/N.

Any help would be greatly appreciated, I've spent hours trying to figure out this part.
Mike...

I sure don't know, but the photo of the slider (below), coupled with the position of the seal, in the drawing, looks like it might fit here ( in the hole near "7" ) ???

Item 13 on Card 31-0315, 31 42 1 231 483, is indeed the o ring that goes in the lower leg on the ATE brake models up to 9/80 with the eccentric adjuster. Item 2 on Card 34-0604, 34 11 1 231 469, is the o ring that goes on the lower end of the eccentric adjuster bolt itself. Both ends of the bolt are sealed.

lmo1131 said:

I sure don't know, but the photo of the slider (below), coupled with the position of the seal, in the drawing, looks like it might fit here ( in the hole near "7" ) ???

Click to expand...

You know, I think you're on to something. While the o-ring won't actually fit into the hole, the brake-caliber-cam-bolt fits in there very snug, it looks like it could fill the gap between that hole and the cam on the brake caliber bolt.

If that is in fact where these O-rings go, neither one of my caliber bolts had them on when I bought the bike, adding to my confusion. Either-way, you've given me hope(light at the end of the tunnel) as to a possible location, so I'm going to go ahead and order two($10.74ea.) ouch! And see if they fit.

Thank you so much,
Mike...

PS: You would think BMW would have put this part with the brake caliber cam bolt parts listing instead of the fork slider tube parts listing. Arrr!

"PS: You would think BMW would have put this part with the brake caliber cam bolt parts listing instead of the fork slider tube parts listing. Arrr!"

The parts lists are done the way they are because they reflect the order, and subassembly stage, the bikes are built in, not the functionality groups. So this brake group part goes with the slider subassembly, which is the stage at which it is installed.
This principle is also why repair procedures in resources like Clymer, which copies the shop manual, will contain excessive labor in some procedures, as disassembly is treated as literally the reverse of factory assembly. A typical example of this is the direction for RS/RT bikes, to remove fairing to clean and lube steering head bearings. The job can be done fine with fairings on, and likely takes less time as well, but in the factory the fairing goes on later, hence it "must" be removed. Undoubtedly this procedure logic also drives up quoted shop labor in certain instances.