remove the actuator cable. take a pair of pliers or crescent wrench and size it to the brake arm. work it back and forth. when it does work back and forth enough, find the center of it's throw. remove the wheel with the brake hub if at all possible. removing the hub by itself can be a pain. when the hub is removed from the spindle, unbolt the actuator arm and remove the brake shoes. once these are removed, tap out the rotator/actuator. inspect the seal for the act. check for pitting, if too badly pitted, it is advisable to replace. get a bottle brush or roll up some 200-400 grit sandpaper and derust the area. that is if it is not full of grease. check the shoe return springs (they hold the shoes together). sometimes the brake material will come loose from the frames and jam up the drum. but most times it is a lack of maintenance after riding in water/mud/sand.