Like you I spent several days trying to drill out a broken M10 motor mount bolt but I haven't given up yet. It was tough to drill through an inch of broken bolt+ drill bit pieces but I'm getting close. Simply replacing the part is an option but I didn't want to risk another broken bolt while removing the part.Thanks for the reply! I ended up getting the AC bracket off the car this weekend. I could not get the broken bolt out though. I broke a few extractors in the bolt and gave up. I ordered a replacement bracket and it will be here today. What a pain!