I've done quite a bit to the E24, but haven't yet droipped the tank. Try posting your question on either of these two sites where there are many more active E24 folk:

http://forums.roadfly.com/forums/bmw/bmw-6-series-e24/
http://forums.bimmerforums.com/forum...play.php?f=237

Actually, it would be best to search the archives on the Roadfly site first. If that doesn't work, then post a question. And visit both often. If you work on your own car those sites are invaluable. Do you have the E28 Bentley manual?