Pedal will not release

Guess there is never and end to these gremblins.
No appearent reason my brake pedal does not return
by itself.
I removed the drums this morning, to check springs and such.
everything seems fine. wheel cylinders are not leaking, springs are
new and tight.
I bleed the rear brakes, got a little higher pedal
checked the master cylinder for leaks, saw none. checked for
air leaks at the power assist unit.. recaped one.
after all that, took the 74 Dart for a drive, although its not
as bad as it was, it still is sticking, this starts at about
pedal half way down.
yes shoes are in the correct placement...

any idea's?
any one interested in buying a 74 dart swinger 318...
$3k its yours. yes
best