problem is usually on the front, took me ages to get mine right. the trick i use now it remover the wheels, brake drum, hub units, and then undo the six bolts on the back that hold the backing plate to the stub axle, and turn it upside down so the bleed nipples face upward, this stops air getting stuck in the wheel cylinders and makes it much easier to bleed.
remeber when you do this though to put the drums back on and do the addjusters up against the drums if you are not using a, air compressor style hydraulic bleeder, if you have acess to a hydraulic bleeder, squeeze the shoes as far into the wheel cylinders as they will go so you have less place for air to get stuck