Be sure you tap the socket into the hole in the bolt with a hammer before you start, to get it to the bottom of the hole. The holes in the bolts can catch gunk and keep the allen wrench from bottoming out. Plus the tapping with a hammer helps to get the bolt loose. If you have stripped the head out completely, Sears makes a stripped/rounded head bolt remover that should get it out. The Craftsman socketed bolt remover has teeth cut on the inside that will cut into the outside of the bolt head and believe me, with a two or three foot brake over bar, something will eventually give.