My speedometer and odometer work fine but the trip meter goes to 99 and stops. The tenth of of mile digit keeps turning over and over. Also the trip meter will not reset to zero. How does these three tie together? I am guessing through the speedometer head? Is this something that I can just leave alone or will this mean the other two parts are next?

 

i dont mean to hijack your post but... i need help in setting mine to all zeros...mine goes through the numbers ok when i drive the car...but the reset does not work i can feel the reset ingage the gears ...it worked fine out of the car....

jack

 

The trip odometer mechanism needs to be rebuilt; the regular odometer and speedo head are probably OK.

 

First, John I would also like to extend my congratuations on your acheivement! You have certainly helped me a lot over the past couple of months being a new owner of a corvette.
Now back to the post, does this mean I have to pull the speedometer or the whole dash? Do you have any recommendations on where to send for a rebuild? Thanks!

 

The cluster has to come out to remove the speedo/odo system; might be a good time to consider having the cluster restored. There are lots of places that do great work on clusters - I'm sure others will make recommendations based on their experience, but some of them are:

Corvette Specialties of Maryland
Joe Ray Parts Co.
D&M Restorations
Corvette Instruments

 

Just had mine done by D&M. Nice people and quick turnaround.

Highly recommended.

 

D&M did a great job on mine also. Great folks to deal with.

 

Sounds like the trip odometer itself has a problem. In repairing that unit it only makes sense to go through the speedometer because 90% of the time, a speedometer failure involves odometer failure. The parts in the speedometer have a greater wear problem when there is a trip odometer. They were not beefier then the parts that were used in a speedometer that did not use a trip odometer, that seems to be why the wear is accelerated. We can repair the speedometer for you, or restore the entire cluster. You will find more information pertaining to our services by clicking on the link www.csofmd.com
When you get to our home page, click on the Restoration tab, then select 63-67 see details.
I will be happy to extend a discount to you as a forum member of 10% through the end of 2008 if you mention this when you send in your work. Other forum members are welcome to join in and we will be happy to extend the same benefit on our restoration services. Please be sure to mention this when you send in your parts. We provide a very specific order form that will enable you to get all of your information together for our services. The form is on our home page, upper right www.csofmd.com

 

I have the same problem. Two years ago I sent my cluster to Corvette Specialties in Maryland for a show level restoration. When I got it back in the car the odometer and trip meter stopped working when the tripmeter hit 199. I sent it back to CS on warranty. When I got it back in the car everything worked fine with the exception that I am unable to reset the tripmeter to zero. I was hoping for an easy remedy. Is this someting I can fix myself?

 

In most cases, if you are unable to reset the trip odometer, it is due to the cable not being routed properly. If you had the odometers replaced, chances are it is not a faulty odometer. The cable is the key. To be certain, check the routing and be sure that when it comes out of the cluster, it goes through the hole in the horizontal dash brace then bends down to the bracket. Sometimes in our shop we have found that a properly routed cable will still fail to zero the trip. In that case, we try to eliminate the cable by unscrewing it and inserting a tool that we have made from a mini screwdriver. We push it in and wind it back that way. If it works, we replace the cable. Really not the greatest setup the General designed for us, and it is even more tricky on 68-77 cars.
I can also be reached by phone if this is not clear.

 

In most cases, if you are unable to reset the trip odometer, it is due to the cable not being routed properly. The cable is the key. To be certain, check the routing and be sure that when it comes out of the cluster, it goes through the hole in the horizontal dash brace then bends down to the bracket. Sometimes in our shop we have found that a properly routed cable will still fail to zero the trip. In that case, we tey to eliminate the cable by unscrewing it and insert a tool that we have made from a mini screwdriver and push it in and wind it back that way. If it works, we replace the cable. Really not the greatest setup the General designed for us, and it is even more tricky on 68-77 cars.

 

I just got my cluster back from Corvette Specialties of Maryland after having the entire cluster restored. I reinstalled it last Friday and it looks great. I have not had the car out yet to test everything but just running it in the garage, everything looked good. Looks like I was a week to early for the discount.

 

Having grown weary of this thing continually malfunctioning, here's what I've done to take the trip odometer out of the mileage solution. (Fabricate a "Z" bracket to hold the trip set **** in the 'up' position. Affix it by means of the inboard nut on the steering jacket U-bolt). The regular odometer wheels still advance each mile. That fragile trip set feature is now not driving at all times.

 

I know positively that the reset cable is routed correctly. The assembly guide has been my constant companion.
The reset cable is something I will look at though. One thing I have tried was to remove the **** to insert a tiny rubber filler and then reinstalled it with a little cement so that I culd be sure it wasn't spinning on the shaft. My hope was to gain more travel as I depressed the ****. That had no effect.

 

I purchased my 64 a couple of months ago and have found a receipt ($506.88) that shows that the speedometer was removed, repaired and reinstalled by ACI last year. If I wasn't so far away from them I would take the car back. So for now I am going to leave this alone and hope the speedometer and odometer keep working. The instrument cluster looks in good shape but I don't see any receipts showing any work there. To: CS of Maryland should I install the Z bracket to reduce the wear or just leave things alone??

 

I would not worry about leaving the trip odometer disconnected. Typically the speedos would fail between 40,000 to 60,000 miles. If you are like most owners, you will not rack up that amount of mileage. Many times, in order to make a quick fix to the odo problem, do it yourselfers would change the second worm gear, and sometimes the third if it was stripped, and the odo would function again. Problem being, the first worm, which is really the main magnet, would remain. In order to replace the magnet, special tools are needed. In addition, a magnetizer, demagnetizer, and a calibration machine are then required to make the gauge read properly.
I can use the old tach drive distributor fix as another way to describe this situation.
How many times have you either tried, or seen another person try to replace only the small tach drive gear when it was stripped? Real easy to do it, don't even need to remove the distributor right?
Wrong, in a short time, that real nice new gear will try to mesh with the old stripped main shaft and bingo, you ruined another small gear. Now it is evident that BOTH gears need to be replaced. Remember when the speedo is properly rebuilt, it should last many thousands of miles, I do mean properly! Often the old odometers look ok cosmetically, but are just too tight and in no time, the gears will strip again.
Haven't you ever wondered why so many Corvettes have betrween 40,000 and 60,000 miles? Oh well I have rambled enough.

 

Brian I think you are right on the money. My records show my corvette's speedometer died at 47000 miles. The records show that the repair facility must have removed the cluster and repaired the speedometer. They must have made the mistake about the small gear on the trip meter. Is there a way to disable the trip meter without the clamp so I can extend the life of the speedometer and odometer? The cluster looks in good shape so I don't want to go there anytime soon. Even though I don't plan on putting a ton of miles on the car I still would like to not stress the unit. Thanks for your help!

 

Since this problem appears to be a design flaw, is there any more or less permanent "fix" for the problem, instead of just rebuilding it to fail again?

Will replacing the second worm with a correct steel worm (see below) solve the problem, as long as the other parts are in good shape?


I found a paper on the Willcox Chevy website (http://willcoxcorvette.com/instructi...suggestion.pdf) that says (in part):
"The second worm gear will be metal if original and plastic if a replacement. The chance's are it is a metal gear unless someone has already been inside and replaced it. When the brass bushing wears out in the back of the head it misaligns this gear to the second worm and wears them both out. You can replace the second worm gear and it might last a little while, but it will probably just eat it right up again." (page 3, after "exploded" diagram page).


From an archive search, I found this post by Forum member gaugetech (http://forums.corvetteforum.com/show...hp?t=2066149):
(NOTE: there are excellent close-up pictures of the internal parts in the Thread mentioned above, I will try to re-post them here to have all the information in one place for easy reference)










QUESTION:

If we replace all of the old worm gears with new steel ones, will that solve the problem?

 

Ok, on disabling the trip odometer. There is a spring loaded apparatus with a conical tip in the speedometer odometer carrier. When it is pushed in by the cable, it disengages the trip odometer from the crossgear. If this part is held in place, (inserted) yes it will keep the trip odometer from turning without interfering with the total odometer. My recommendation for keeping the trip from turning would be different than the clamp on the cable deal. I would remove the speedo and reposition the crossgear on its shaft AWAY from the trip odometer. this is easy and easily reversible. I would be happy to coach someone over the phone on this procedure, (please have all pieces in front of you if you call). I would still leave the trip hooked up. I know we all get finicky with these cars, I do too! That being said, you are not putting your car to any unnecessary strain by leaving it as is.
Second question, by replacing magnet, (or first worm), second and third worms with new steel pieces, it will not make the problem disappear. The bronze bushing that is pressed into the main frame must be correctly sized to maintain alignment. In addition, the 2 thrust washers must be installed, and the flare on the magnet must be done properly to maintain the proper thrust or end play. If all of these are done properly, we then have a speedometer that should be no better then it was new! (as long as the odometers are not too tight!!) And it will still probably fail between 40,000 and 60,000 miles!!

 

A picture of the trip wheel:






Even when using a square headed screwdriver to move the wheel, it still takes a pretty good push to engage the gears. I would suggest that some aren't getting enough travel in the cable.

P.S. Never try to reset the number wheel while the car is in motion.