I have a 1950 3100 Chevy. The speedo was not hooked up when I bought it. I dissembled and cleaned the speedo. I ran a test by hooking a drill to it and running it in reverse. It seems to work right. Then I bought a new cable and installed it. It worked for about 1/10th of a mile, then went down to zero. I checked the cable and it appears to be fine. What could be wrong?
