Front Caliper Carrier Bolts

[$chlitz]

Update: Yesterday I went to do the brakes again, this time starting with the passenger side, which I didn't try last time before I got discouraged. Both carrier bolts came right off with a quick zip from the impact gun, and FWIW, the new bolts with the 18mm head were a direct fit. Exactly the same as the 16mm bolt I pulled out, other than the change in head size. Had the passenger side pads and rotors changed out in a half hour. Back over to the driver's side...

Bottom carrier bolt came out using a breaker bar and a 4ft pipe on the end...but that top one is fudged, for sure. Tried breaker bar and pipe, but 6pt 16mm impact socket just slips off eventually as the head was slightly rounded off when I tried to get it off the first time. Tried heating it (I only have a MAP gas torch), no luck. Went at it with the impact and that sucker didn't budge. Now the head is fairly rounded off and the impact socket is even slightly damaged (still usable, but noticeably damaged).

Anyone have any other ideas how I can get this damn bolt out? I thought about grinding off the head, but it's actually threaded into the caliper carrier itself, which is in between the bearing carrier and the rotor, so I'd still have to figure out how to back the bolt out of the caliper carrier in order to remove it. If the head wasn't rounded, I could maybe get it with the breaker bar/4ft pipe combination (only tried the breaker bar last time, before the bolt head started to round), so I'm thinking of trying one of those turbo sockets to see if I can break it loose with the pipe. I'm certainly open to any other ideas.