<VV> Always that last bolt......Suggestions from the group

[henry kaczmarek]

Greetings all. 

Since it's a nice 70 degrees today in the Foothills of NC, I decided to finish pulling the drivetrain from my red 60 700 4dr PG. 

After disconnecting everything, and remembering to take out those 2 bottom bellhousing bolts, before going to get my engine removal cart, I decided to loosen the mount bolts just to make sure all would go smoothly when I drop the car on to the cart. the rear mount bolt and the pass. side trans bolt loosened right up .
The Driver's side fulfills the prophesy---THAT LAST BOLT---You can't get it loose, and the socket isn't fitting on it correctly. 
  I'm using a 6 point 11/16" socket.
  I pulled out ALL of the cotter pin. Cant feel any metal sticking out that could have been a piece of the pin I missed. The socket still won't seat all the way down on the bolt. 

Time to take a break and ask---What the hell could I be doing wrong?  Will perhaps a metric (16mm) socket do the trick? 

Any ideas? 

Hank