I have fixed a few of my old car clocks. There is a spring that winds down every few minutes, then, the contacts hit and makes the contact, and throws the spring back. After years, the points need cleaning. Take the clock out, then the back cover off, and file the points with a nail files, or fine file, just like the points in the ignition. That is almost always the only thing you need to do. Note, there is always a chance it could be something else, but in my experience, that is all it has taken for me to get my Studebaker clocks working. I have not gotten around to doing my 53 Manhattan yet, but, I am sure it will be just as easy. Best of luck.