There is a major adjustment and a minor adjustment, We all should do a major on our trucks when we get em or replace any brakes, this means find the holes in the hub that allow access to the top and bottom adjust ment meaning sliding a measuring shim in there to measure brakes from drum., I beieve i remember the top space between the shoe and drum should on each side be 20 thousands and the bottom 10 thousands, it will take a few times back and forth to get em all correct, after 3000 miles we are supposed to do a minor that means just do the top, then another 3000 miles a major again. not doing this can lead to a spongy pedal or a peddle that can make u think there are other things wrong, this is the first thing to do always,besides looking for leaking cylinders...