Forum bmwbike.com

I want to post this information for singles owners who may encounter the same problem I had in getting the correct seals for their final drive units.

Mark's catalog and the BMW parts book both indicate the correct numbers for the 2 seals in the final drive that install circumfrentially to the rear axle. These are the crown wheel seal, p/n 31 11 3 004 140, and the axial seal, p/n 33 12 3 004 188.

The problem occurs in finding the right seal for the drive shaft side of the final drive. This seal fits around the pinion shaft, and the BMW parts book lists an incorrect number, p/n 23 11 1 030 540. A search for this part number in Mark's catalog yeilds "no entry found". However, a search of the drive shaft section of Mark's catalog reveals a drive shaft seal ring, p/n 26 12 1 030 541, which is indeed the correct part number, and is available from Mark, but this doesn't appear anywhere in the BMW parts book.

Dave,

In the BMW Auxiliary Catalogue supplied by Mark, the seal is correctly identified as seal ring p/n 26 12 1030541 in the R26/27 section

Gentlemen!

The problem is as follows. When BMW changed the specification on certain parts, the part got a new part number e.g. In older catalogues, the part no. in question 23 11 1 030 540 was perhaps made of a compound that was not hypoid resistant as the final drives used normal SAE 30. With the introduction of hypoid oils, they had to change the material specification of this oil seal and hence the new part number 26 12 1 030 541. This number first appeared in the parts catalogue from 1.10.1967 in addition to the old number. However, to add to the confusion, it was given the incorrect main- and sub- group numbers "24 12", and the english translation was incorrectly given as "Ondulated washer". This was corrected in the last parts catalogue from 1.07.1972.

Normally in such cases, we list the old part number in our on-line catalogue, with the text "replaced by 26 12 1 030 541". Unfortunately this is a tedious process which still has to be completed.

Best regards,

Mark
Mark Huggett GmbH

Thanks for the clarification Mark. While I was waiting to hear from you I found a New Old Stock seal with the original part number, and we installed it in my final drive. I guess I'm stuck with using motor oil now, until I have time to install the new seal.