Woah, be very careful not to break it, especially if you have the bolt with a cone. If tha breaks, then it will have to be extracted out and you might get some wheel damage associated with that. Try going to a place that cares for cars and will use some slow technique of taking it off until its loose enough. I heard that mercedes bolts should not be tightned by machine but rather by hand or a torque wrench. If you keep forcing a high powered tool on it, it will eventually break. Maybe try heating bolt up? I learned my lesson when I overtightened my bolts by hand and when my mech took them off, they broke right off! And so I had to leave my car in the shope and extra 4 days! It took so long for the bolt to get off and I got some wheel damage on top of that.