I know this is a very very old thread but for those of us still driving the w210 I thought this would help. I sheared the lug bolt off my 1999 W210 e320 4MATIC sedan - what a bummer! It was my fault for over tightening with my impact wrench. It took hours of attempts at using an easyout bolt extractor then 5 welding attempts to get a nut end to hold on under the necessary torque to free the bolt. Finally she came out. As mentioned MB stopped selling these long (84mm) bolts - you cannot buy them new from the dealer or from a second manufacturer, the design has been scrapped. Instead you get a much shorter bolt that sits deep inside the wheel bolt socket - you cannot see the lugs. Ebay has the old long bolts (used) for as high as $20 per bolt!

Im going to replace all the lug bolts as I never want to live through breaking one again! Below you can see my broken bolt head and the welding done to put a nut on the broken shaft to extract.