I just recently started rebuilding a speedometer for a 36 ford as well as one for a friend. I found that to repair the green film in some of the early speedometers you can use green high temp tape used for powder coating to make the green tint for the bulbs. I just pulled about a foot, folded it in half. Stuck the two sticky sides together and it worked perfect. I'm not even sure if the make a replacement tint or not. Also on the top part of the speedometer where the cable goes in there is always a small plug somewhere to oil them. That usually breaks free the mech with a day of soaking with oil and some slow speed on a drill and I've got every one to break free.