My original 'gasket' holding the mirror in place finally wore out, ejecting the mirror onto the road, luckily the mirror did not break, and I was able to retrieve it. The problem is finding the gasket that holds it in place, does anyone know where to get this?
#12 is available for the early trapezoidal mirror, if that's what you have. You can purchase it directly from Maximillian or use the part # to check price & availability from your local dealer. There should be a spring that "pushes" the glass out from the metal housing and against the seal. http://www.bmwmobiletradition-online.com/bmw/showparts.do?model=ST12&mospid=47140&btnr=51_3343&hg=51&fg=40
If you don't find it right away, try calling Brian Scroggins (aka 'Da Parts Pimp') at BMW of Chattanooga. If he can't find it for you, BMW doesn't have it.
The gasket became available recently, but I've never replaced one - I'm sure there's a trick! There is a pair of the mirror "heads" for sale on eBay - trapezoidal metal head, glass, gasket altogether: http://cgi.ebay.com/ebaymotors/BMW-2002-2800-CS-3-0-CSi-E9-tii-Bavaria-MIRROR-HEADS-SQ-_W0QQcmdZViewItemQQhashZitem230e332c95QQitemZ150562090133QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories CR's right - Brian is very helpful & knowledgeable, with great pricing.
They aren't too bad to assemble. A little like popping a windshield in. I would not buy old ones. These parts are a nylon plastic that degrades with age and exposure to air. That's why your old one failed, as it did on my Bavaria. The last time I bought any, I think they were around $3 - which is to say they're probably around $20 now.