I have a 1957 Saratoga. It was acting oddly, like the linkage was
sticky. I oiled it, and even put a second spring on the pedal to pull it
back up.
I finally found that it was the short flexible rubber line between the
master cylinder and the frame, that had swollen closed. Apparently, this
is a notorious condition. When I replaced it, all the troubles went
away.
Good Luck, and let us know what you find.
Joe
Savard
Lake Orion, Michigan