I just finished renovating the oil/water pump on my 87 K100RS 12/2011

I used K-freaks compiled tech articles as an instructional guide.

There are some part number changes that have come into play since Jan 2002.
Quote:
Service announcement from BMW
"All K75, K100 and K1100 now share the same slip-ring seal, spacer and impeller as the K1200 RS/LT"

Metal impeller 11 41 1 461 173 ($14.26)
Spacer 11 51 1 464 902 ($7.65)
Slip ring 11 51 1 704 084 ($24.54)

The 'O' rings:
11 41 1 460 328 ($1.02)&
11 11 1 460 392 ($1.69)

And Shaft Seal
11 41 1 460 329 ($10.42)

are also needed.

Prices from MaxBMW as of 12/2011

These seemed to go together quite well and aside from me being a little squeamish about driving a screw-driver into the housing to release the original seals not very heart wrenching.

Cheers, M

Good on you for sharing those most helpful.
Regards,
K-BIKE