Classic/Antique Car Repair: Speedometer, speedometer drive, speedometer cable

Question
QUESTION:  My speedometer and odometer,on 1973 Buick Rivera have quit working.Can this problem be a cable?
 Walter

ANSWER: A question for you. Do you have cruise control?
Brad

---------- FOLLOW-UP ----------

QUESTION: Yes I do have cruise control,but it has not worked in 3 years,The speedometer worked in that time frame.
Thanks Walter

Answer
Ok, this is the way that I check out a speedometer and cables. I jack the rear wheels off the ground and support the rear axle with safety stands. Under the hood locate the speedometer cable that comes from the transmission and connects to the cruise control servo. Disconnect it and start the engine and run the car in drive. Watch the cable end to see if it turns. If it does not then that cable, the lower cable, is either broken or there is a problem in the transmission with the speedometer drive gear.  If it does shut the car off and reconnect the cable. Disconnect the other cable and watch the drive in the cruise servo to see if it turns with the engine running, in drive and the rear wheels turning. If it does not then there is a problem with the cruise servo. If it does then you need to disconnect the speedometer cable from the back of the speedometer and repeat the test. If it does not turn then there is a problem with the cable and if it does turn the problem is in the speedometer head.
Brad