Well I was removing my main engine crossmember so I could remove my lower control arms in my 65 and I broke one of the bolts. So what do I do? Do I weld it up? Do I drill it out and retap it? OR?????
If it did it's large enough to drill and remove with an EZ-out, I think. The question is why did it break!
If it broke because it's rusted in place it will be very difficult to remove!
You may have to drill it all the way out and install a Heli Coil.
(if you are not familiar with Heli Coils, google for "Heli Coil")
If it's rusted in place though you may have other problems, like frame rot. (rusted out frame parts)
That bolt being rusted in place can be a bad omen for other problems in the framerail like Roy said so check it out real well. You need to get it out and remake the threads somehow and once you do USE ANTISIEZE on the bolts. I use it on EVERYTHING now.