Peak force to debead at 0 psi with some wood jamed in there: 1271 lb.
Cleaned up, reseated the bead, hear a hissing sound and find the valve stem is torn.
I didn't have any regular replacements, just the emergency ones that you put on from the outside. Which I didn't want to use, so I got some, broke the bead again and put in a new valve stem.