The Results Show:
A couple of things happened, so I'm not going to be sure of the exact cause of my previous problem. But I'm going to have to believe that I just was unlucky enough to have had a bad keg.
1) Replaced the check ball & retainer (To answer my own question, yes the check ball can come out if that retainer comes out)
2) New Keg
And I have Wild Beer no more
Now I did inspect the seal around the top of the keg that I was replacing and didn't see anything obvious that could have been wrong with the seal or anything else.
Thanks for all the help,
Gary