1965 GTO speedometer Issue
 

Since I posted about my temperature gauge I figured I would ask about my speedometer.
It starts at -10 and accelerates normally but is off by 10 MPH.Another words,if I am doing 30 MPH it show 20 MPH. Here is what it looks like when not moving.Does it have to be re calibrated ? Maybe it is missing the resting pin. Has anyone ever had this issue.

Well if it's resting at below 1, than yeah it will be off by 10 mph at whatever mph your driving at!

I just checked my 64 GTO speedo[it's apart as far as the plastic cover is concerned], and there is no pin to stop it. I can move the needle with my finger and it goes back to zero. It feels like a positive stop, so there must be something inside it to act as a stop.

I just got the car so this might have to wait till winter to lay it up. I just put this out there to see if anyone has ever run into the same issue.It seems like it is in the gauge than the gear going into the transmission.

IF you are sure it is off by 10mph throughout the entire range then simply pulling the pointer off and resetting it at zero would calibrate the gauge. You must pull the pointer straight off so as not to bend the shaft. You also want to make sure it isn't glued on before pulling to hard because you can damage the mechanism. A bit of heat from a heat gun or hair dryer will soften most glues enough to pull it. I always used a two part 5 minute epoxy to set a pointer on. You only need a small drop on a tooth pick inserted into the pointer before placing it on the shaft. It takes a while to set up so if you need to reset the pointer a few times to get it correct you can.

Never used glue. Hold shaft with needle nose pliers and rotate while pulling to get off. Hold shaft and rotate while pushing to get it on. From the service manual.

Charles

That's how we did it when I repaired and calibrated flight instruments for helicopters. A measure of common sense never hurts. If the fit is tight enough then obviously glue may not be needed. Pilots hate it when a pointer pops off in flight. :D You can't go wrong following the service manual.

What Charles and Luxury said. Big time.

I think there is a spring adjustment in the back to calibrate. I have not had one apart in 30 years. It may be best to take it out, drive along with another car known to be accurate and adjust to the same speed.

Exactly how I do it also. I wouldn't even bother to pull it off, just hold the shaft with the needle nose pliers and twist the pointer to zero.