I am in process of rebuilding my brakes on my 69 lemans. I have drum brakes on the car. After finishing I realize 3 of the 4 automatic adjustors are not working. I am trying to figure out why. On the front brakes there is a washer at the top of the brake shoes where the spring hook.The hole in the washer is oval shaped. Should this hole be oval shaped or round??? I have researched this part online and can not find any information on it.