It started with the simple replacement of the front exhaust pipe after breaking, yet one of the studs wasn't going to let it be so easy.

My approach started with cutting a slit in the bolt and a slotted screw drive on the end of a socket, but I quickly gave that up in favor of boring a 1/4" hole into the bolt for a reverse-thread extractor. Despite the extractor getting a nice grip and several days of dousing the area with pb blaster from both sides, the stud was still not going to budge. Rather than grabbing a longer wrench and risk breaking the extractor in the bolt, I opted for brute drilling and chiseling.

The pic shows a 5/16" bore in an m10 bolt, about the largest possible without getting into the threads. In lieu of a die grinder, I do have a dremel .. maybe grind away at what remains with a carbide bit on low speed? Then maybe work at cutting what remains with an m10-1.25 tap? It is thin enough at this point that I would also consider going at it with a screwdriver or cold chisel and a hammer, but something long lest my hands be in the way. Any points of advice people have for putting this one in the bag?

 

Heat and a easy out maybe? There isnt that much left of that bolt in there.

 

Just drill it out and tap it to the next bigger size...

 

Yes, tap it to a larger size. Or if you're picky, helicoil it.

 

Finally got this one -- tried using the extrator again but it wasn't catching so I went at the thin side of what was left of the stud with the dremel then peeled back the threads with a flat screw driver until I could twist the rest out the back .. after all that without much visibility, threading a bolt through now, it seems to hold surprisingly well.