I have been having a strange issue with the right rear brake drum on my runner. When I am approaching a complete stop that one rear wheel will lock up and drag the tire. When I release the brake pedal it usually takes a couple seconds before the brake will unlock. Sometimes when sitting at lights it is very noticeable that the brake is sticking when trying to accelerate and it is dragging the truck down.

I tried to see if the brake was adjusted too tight so I loosened up that drum considerably...tire still locks up. I pulled the drum off and there is still plenty of brake material left and no strange wear. The wheel cylinder and axle seals are not leaking either. Is it possible it could be the wheel cylinder? Usually I think a wheel cylinder failure is the other way around, no brake power. Any ideas of what it could be?

You could just try replacing the wheel cylinder and see if it corrects the issue. At Autozone I paid $15 for one, so you wouldn't be out of a lot of money.

Yeah thats what I'm going to do first, along with a brake hardware kit. Got both from Advance for $20.

Also check the backing plates where the shoes contact them. They could be grooved or rusted through and causing the shoes to stick.