I was trying to remove the balljoint pinch bolt from the steering knuckle in my 2001 Legacy and the head sheared right off. If I were able to get in and drill out the bolt without damaging the threads, does anybody know the sizing of the bolt I would use to replace it? Any pointers on removing the old bolt are appreciated too... It's my first time attempting to replace a sheared bolt like this one!

Try using a punch and hammer before you drill it out