Bob -

That's interesting. Mine failed in exactly the same manner, exactly the same location. To me it almost looked like acid damage from the battery, but there were no other signs of spilled acid. Like you, I've no idea what caused the rupture.

After repairing on my '93, in addition to not having the air conditioning blow out the defost vents during acceleration, I also noticed the transmission shifted more smoothly (more vacuum), and the idle was a bit smoother/more stable (less unmetered air). It's a good little fix.

- JimY