Sounds like you need to loosen off the brake adjuster, this is a cam system and the shoes will be rubbing against the drum. There are adjusters on the back of the drums. Jack the axle up and loosen the adjuster off fully on both wheels then tighten them up until you can hear the shoe just rubbing against the drum, both adjusters should be on the same adjustment or your brakes will pull to one side when you brake. On the adjusters you will feel clicking, do both adjusters the same amount of clicks when tightening them up.
