go to SEARS and buy those screw/ bolt extractors. you drill a small pilot hole and then use those extractors , they grab into the hole and unscrew it out . I did this on a screw head, but i think in did bolts too. Do what I did , buy the most expensive set, use it, then return it. Free tool rental.

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1996 E320- 18" Chrome AMG, Bling Bling Mirrors