[SJLenz1340]

I still have 4 drums, adjusted all and then had a similar problem. Given the age I replaced everything on the rear, springs, shoes, drums, adjusters, hose, wheel cylinders, and e brake parts. After all that my rear brakes work great, and with such a grand success I have all the same parts ready for the front.
It is my opinion that I had perhaps several issues, 1) worn out adjusters 2) failing wheel cylinders, the muck that came out of there was bad 3) I also suspected the brake hose, seen that fail before.