Didn't know the auto tensioner bolt was reverse thread! snapped it .. anybody ever broke this bolt before? any suggestions on how to get it out? is drilling it my only option?

 

Get a dot punch (sharp point) and tap it near the perimeter so that the blows undo whats left of the bolt. It sometimes help to strike it square to put a dimple in it before leaning over the punch and hitting it at an angle to rotate it.

This technique should work easily provided the bolt isnt tight in the threads or it hasnt bottomed out in the hold.

Otherwise, if you drill it the facts its a reverse thread will hopefully back it out if the drill grabs.