Finally been able to drive my ‘68 having ironed out its brake issues. Took it to work with me for the spring auto show and swap meet at Raceway Park in NJ.
I parked it on the track in the show and it got a lot of attention and kind words, ooohs and aaaaahs. I’m one of the guys running the show so it’s exempt from a trophy but it was its unveiling and with everyone’s approval I feel like I got more.
Anyway, I put about 80 miles on the car and the odometer didn’t budge , the speedometer did work so I’m thinking the odometers gear stripped???
the trip odometer isn’t working either.
Is this difficult to fix ?
I just finished repairing to factory standard burnt wiring under the hood, rebuilt the Tri-power set and the rebuilt the rear brakes including the entire parking brake system so you get an idea of my ability. Only problem is my old gorilla hands with the small stuff .
What do you think I would I expect to find wrong?
Thank you in advance for you input on this and again for prior input for what you’ve helped me make right


Soft top on Sunday

Hard top still on for Saturday

 

There's a shaft inside the speedo with gears on both sides. I don't know if all are plastic from the factory but mine was and it snapped. I replaced it with a metal one I took from a repro speedo but I've seen them for sale separately.

Not a difficult job as long as you're OK working on small things. Be careful pulling the speedo needle/pointer off. Easy to damage something as it can be stuck on there good.

Whatever you do, don't buy a repro speedo. I bought 2 of them and they were absolute junk. Original is much better made.

 

Check to be sure your "trip" reset is fully pulled down. If partially up, it disengages the odometer.

 

It wouldn't disengage the primary odometer, just the trip odometer. Unfortunately the only fix to the speedo odometer requires pulling the dash out which is no fun job.

 

i ended up doing this job when I went from auto transmission to manual, since you have to remove the entire dash in order add the 3rd pedal to the pedal assembly.
If you're careful, you could probably lower the steering column in order remove the driver side dash with the gauges.
I had 2 main issues when I repaired mine:
1. The worm gear was stripped
- Not that bad of a fix. Many metal gears are available for purchase, but the best way to do it is to replace with a plastic one, if you can find it. This plastic gear gives a known weak point so the rest of the gears don't get trashed. I couldn't find a plastic one, so I had to replace with a metal one.


that's the metal replacement worm gear

2. The number rollers on the odometer and tripmeter were frozen/stuck on the shaft. I think this is the reason why the worm gear got stripped. If you see how the mechanism works, you'll see that the speedometer turns that worm gear, that then turns the number rollers. I had to fully remove them and carefully free them up by working them back and forth, and putting the TINIEST bit of penetrating oil on the shaft. Be careful, though, the penetrating oil can make the printed numbers rub off.
The shaft looked a tiny bit corroded, so when I freed up the rollers, I used some steel wool to get rid of the corrosion make sure it was smooth.
(you can see that grey spot on the copper colored shaft; that's the corrosion I'm talking about)



If you go through all the trouble to remove the dash, speedometer, etc. I would make sure you check those number rollers, or you may have to do it all again.
Don't just replace the plastic worm gear

 

Good photos above!
I would also like to add, you can see in the 2nd photo above there is a small spring between the 1/10 and a smooth brass bevel section of the brass shaft.
When the reset cable is pressed in it allows the brass shaft to move just enough to disengage the side idler gear so reset can happen.
If that shaft is sticky and doesn't return the brass trip shaft gear will not make contact with the side idler gear that is the drive for the trip odometer.
That is the function of that tiny spring.
(1) Reset Cable Home position
(2) Reset cable pressed in

 

My trip meter cable was pulled out of the bracket when I got the car and was just hanging in space. I will check this thank you.
Mongoose, thank you. That's a lot to absorb but I'm sure to refer back to it.

 

Removing and Then reinstalling the speedo and tach on my 73 convertible has been the toughest job that I have done on my car. That being said, you only want to do it ONCE. Take both to a highly reputable shop that has loads of C3 experience. My shop told me that my speedo and tach had never been serviced/repaired, so the cost was not cheap. I lowered my steering column and the hard part is getting the old wiring harness to set on top of the speedo and tach. A real nightmare.

 

I've removed the dash after just lowering the steering column but I recommend removing the column from the car. It's only a few more bolts and makes the job so much easier. I remove the 2 bolts from the rag joint so I don't have to pull the rag joint flange off the shaft.

If you also remove the seat the dash job is not bad as you can easily slide under it. If you're not worried about originality consider adding a quick-connect to the dash wiring harness. I used a couple weather-pack connectors so I don't have to fight the bulbs when removing.

 

We’ll see, this is my first Vette but not my first restoration by a long shot.
Once I get into it I’ll know, have to change the cables anyway. I’ve repaired things that other mechanics threw their heads up on. There’s differences In the Vette for sure. Lots of help here preparing for that.

 

There is a guy who has a stand at Corvettes@Carlisle who does nothing but Corvette Gauge restoration and repair. He is usually on the same aisle as Van Steel and they do excellent work including refinishing the gauges. I believe it was Corvette Instrument Service and they have everything you could need in addition to being able to rebuild the original parts. I see they sell LED Instrument panel light bulbs 20 for $25 if you were still looking for the bulbs. They are online.

 

ok thank you