after you assemble the brake shoes and hdwe on the backing plate, as a check I always pull on the adjusting cable several times to make sure the adjusting pawl is engaging the teeth of the adjusting wheel correctly, and advancing the screw, and returning to the next tooth correctly.
There is always the possibility of a frozen emergency cable, also. When the cable is pulled and then released, the cable may not retract fully in the sheath, therefore applying undue pressure on the brake shoes. A little extra pressure can be enough for unwanted brake drag, and extra heat.
