Long shoe in back and short one in front? Possible bad or crushed brake line or hoses.
Also is the self adjuster installed the correct way?
AFAIK, a '69 RR with drums are not self adjusting.
How old are the brake flex hoses?
A hose can get a rupture in a way that will act like a check valve and not let the shoes retract fully.
Jack up the bad wheel, pump the brakes till the brake locks up, crack the bleed screw to see if it releases.
Wheel bearing was mentioned. Make sure the cotter pin is locking the castle nut adjustment. A right side unlocked castle nut will tighten bearing adjustment, a left side will loosen.
