Interesting info. I was studying the pictures throughout this thread and have the following questions. where does the extra black bracket bolt to? On the holes that you highlighted with arrows, do they by any chance line up with the commutator brushes? My thoughts were that they may have had something in them holding the brushes into a retracted position while the end bell was inserted onto the motor housing to be removed after it was all bolted together allowing the springs to push the brushes against the commutator. I would have to study the park mechanism to get a grasp on it. I saw in your article, a thermal switch which I would not have considered but it does make good sense. It looks like they use an internal resistor for speed control over some sort of transmission. I don't yet understand the pawl and gear mechanism. Maybe it is designed to give some sort of relief in case the wipers froze to the windshield. I really think that the spring loaded contact plate that you show broken and the other spring plate are not beyond being repaired/reproduced. Don't throw that thing away or give up on it yet.
