By saying "going out of adjustment", I am assuming you mean that the adjuster screw is vibrating, turning and making the brake shoes not be pressed to the drums enough.
When we adjust our brakes, we turn the screw until the drum barely rubs on the shoes as you pull the drum on and off. The way to keep the adjuster screw from turning loose from vibration is to install the spring backwards. The long coiled section of the spring should be over (and in contact) with the "toothed" adjuster plate on the screw. This will "lock it down" and prevent it from turning loose.