gleninsandiego

My speedometer on my 69 was consistently reading about 10 mph. too high. (I have a gps speedometer app on my cell phone) Yesterday as I was driving about 60 mph I looked down and it suddenly was reading about 100 mph and then it went to zero where it has been since then.

I am assuming this is the speedometer itself and not the cable or trans but will check later

If it is the speedometer, what are my options? Is there a "go to" place for repair of my unit? Or is it cheaper to replace with a new or used one?
Does anyone make a gps one that looks like the factory one?

Thanks
Glenn in San Diego

corvgreg

Seems strange to me, the cable usually binds causing a bouncing speedo needle. There is a plastic gear in the transmission that the speedo cable goes into. The problem may be there.

gleninsandiego

I will take a look

TimAT

One of the other members here lost his speedo on a long road trip. The square for the cable in the driven gear in the trans decided it wanted to be round.

71VetteLover

The mechanical speedometers have a coiled mainspring in them and when the spring loses its tension or breaks the speedometer will read higher than normal.

Alan 71

Hi Glenn,
After checking the gear and cable as Greg and Tim suggested…..
If you decide you need to have the speedometer itself repaired you might consider bringing/sending it to Corvette Specialties of MD West. They're in Palm Desert.
They used to be located on the East Coast… that's why I'm familiar with the work they do.
Regards.
Alan

Primoz

I also have a ticking noise coming from my speedo and the needle bounces at around 20mph but the it stops.
Same symptoms?

midigike

Primo

Most likely the cable as well, mine would bounce around after 40mph and would dive about 20-30 mph. If I went slow and steady no issues. I decided to change the speedo cable and it solved my issue. When I was playing with the old cable the 40 year old grease was like clay. This was about 8 years ago and still working good.

Primoz

Quite some work involved? Dismantling the dash?

george2066

if it died like mine, for now i am using digiHUD as a gps speedometer until and if I have to tear out the speedometer

midigike

I'm a small guy with thin noodle arms and I was able to unscrew it out and swap it. It would help if the drivers seat was out. So I did it without dismantling the dash. But it is very tight. Have a beer before you start to relax.

gleninsandiego

I pulled the speedo cable at the trans, put a drill motor on it, and it didn't budge the speedo needle. I then pulled the cable at the speedometer and ran the drill motor again. The cable was spinning at the speedometer end. However, what should the end of the cable look like
at the that end. I looks a bit wimpy to me. Is this what it should look like? Here is a pic

CanadaGrant

I would say it is sheared off and you will find the rest of cable end in the speedo. Your missing a half inch or so of the square cable end that drives it.

gleninsandiego

Well that would be better than having to fix the speedo
If so, now I have to figure out how to get the other piece out of the
speedo without pulling it

Alan 71

Hi Glenn,
I'm not even sure how the sheared plastic part got out of the speedometer mechanism?

Perhaps when it's distorted that much it can slip out of the fitting at the back of the speedometer case.

Regards,
Alan

HeadsU.P.

That looks like some kind of aftermarket repair tip.

Alan 71

Hi,
I've been under the impression that the first drive gear in the speedometer was metal.
Weren't they?
Could that be a replacement?
Regards,
Alan