The rudder cam on the starboard side of my boat won't lock by pushing on the tiller bar. I have to lock it down with my foot. My boat is a 1974 model and I believe the problem is the cam has been drilled out so many times it creates slop in the cam assembly so the cam sits back in the casting too far and the upper casting can't catch the cam to lock it in position. Any ideas how fix this problem without buying a new lower rudder casting?