kann man aber machen DIY
ich zitier mal:
...can now report that i have managed to repair the Distributor cap center carbon brush, the carbon brush is attached to the center by a small spring, just pull out carbon and spring, keep the original spring and replace the carbon brush with similar size, i found a FIAT carbon brush to be the exact perfect size, when you have replaced carbon and spring check electrical continuity from new carbon to cap igniton coil connector so your assured a good electrical connection. 
Hope this helps,Thanks. slydon.
 http://www.bimmerboard.com/members/s...utor%20Cap.jpg