Do you have the truck off the ground so you can spin the wheels while adjusting the brakes? All four brakes need to drag when adjusted, then you can go through the bleeding procedure. Spin the wheel both directions while adjusting the brakes, that helps center the shoes in the drum for a tighter adjustment.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy