同意楼上二位

This brake system does have an auto adjustment mechanism. That is what the star wheel for. You should see the 拨叉 which prevents the star wheel from turning back. Every time when you pull the parking brake, you allow the star wheel to turn towards the tighten position. That is why it is recommended to use the parking brake every time when you park your car. However, you want to set it tight when you install the new brake shoes. You should found a hole on the back side the housing unit right behind the star wheel, and it should be covered by a rubber plug. After installing the drum, you can ply the star wheel with a screw driver through that hole to tighten the brake. If you have an uneven tough of the shoes, you can push down the brake paddle to reset the position.