I had the same thing, I tore it apart, my back ones need atleast one new drum because something got between the shoe & drum. There were pieses loose for the Emergency brake one one side, I found the problem! I tore the front apart just to look. I have heat & stress cracks, one is so bad the crack is a split in the rotor. I will have over $600 in parts before I get done.
I have only put 10K on this truck, NOTE to self: When buying a used truck inspect all brakes before the warrinty runs out!!!!!!