Speedometer Bounces Around

My speedometer bounces around. In my 1950’s GM cars this indicated that the speedometer cable needed lubrication. Is this also true of the 1965 MKII? If so or not, what should I do?


In my experience with 53 years of ownership of a 3.8S a fluctuating speedometer needle is an indication that the speedo cable is worn. When this happens the cable winds up and unwinds in rapid sequence causing the needle to fluctuate. I doubt that just lubrication of the cable will cure your issue but you can give it a try. You might be able to simply have a new inner cable made up using the old one as a pattern for length and rethread that into the outer casing with proper lubricant. Ensure there are no sharp bends in the routing of the cable casing as these promote inner cable wear and the issue you are experiencing. For many years my MOD 3.8S was running with no 90 degree angle drive at the gearbox end and this resulted in the cable making a large bend in its routing to the engine bay and to the fascia instrument. Once I fitted an angle drive to the overdrive that greatly improved the cable routing and periodic wear out of the inner cable was greatly reduced