A while ago my odometer broke. It's an 88, so it's to be expected. It's the main drive gear, right? In May I had my favorite shop in town take out the console, and they sent it, with my new gear, to a specialty instrument shop (Palo Alto Speedometer). All was good, until now. It's broken again???

Any ideas?

-Sean

 

The new gear material is of a much more robust material than the original..so you say the "gear is broken"? Are you certain the gear is broken or is it a matter of the odometer has stopped working? If the gear is once again broken you must have gotten a NOS Porsche gear that crumbled, not one of the gears being offered by our various 928 suppliers and Rennlist sponsors.

If it is a matter of the odometer simply not working once again, then there are at least 2 things that need be checked on the new gear. 1) casting nubs on the side of the new gear that will stick from time to time on part of the odometer frame. In this case the fix is to shave off the nubs and reassemble. 2) in some cases the new gear is slightly larger than the original gear. It will work for a bit and then ultimately bind up on the worm drive itself. The fix in that case is to place a thin spacer under the mounting screw for the motor that gives just a bit of "freedom" to the worm gear/driven gear mesh.

There are other possibilities that will bind up the odometer also, I think Dwayne shows a very detailed process for checking out other issues in the odometer. http://dwaynesgarage.norcal928.org/1...0Procedure.htm

While his car is an '84 the odometer section is virtually identical to yours IIRC. I would not expect either your repair shop or for that matter PAS to understand all the issues in these things.... sorry, but the pod will have to come out again...it is well detailed in Dwayne's writeup....I have had the pod in and out often enough on several 928's that is is becoming only as bad as root canal therapy....

 

Why i don't bother fixing mine....
You didn't play with it while it's moving did you?

 

Yeah what I meant was just that the odo stopped again, don't know why. So thanks for suggestions, possibly I am not up for another $300 to send this over to Palo Alto, I dunno yet. It is annoying and is depressing the value of the car, seems like it is worth it to have working odometer with realistic mileage, because of the value differential according to auto appraisers.

And no, I did not reset trip while moving.

Thanks,

Sean

 

Sean, FWIW taking out and replacing the odo gear is an hour job that feels like 45min. Doing so will also allow YOU to inspect the other 25yr old gears, in case they lost the battle with a new stronger material replacement.

Once you do it once, it is a 30min job to pull the instrument cluster...lets you clean up the dust under the plastic as well.

 

Warranty?

 

Not expecting much in the way of a warranty on this. My local shop did what they were asked, which was remove and reinstall the pod. They even tweaked a few old connections and helped some stuff while they were at it.

The subcontract to Palo Alto Speedometer *might* be subject to warranty, but again, they did what they were asked, which was to replace the main gear and verify the odo worked. Which it did for the past few thousand miles.

So, my local guys are just going to sigh and laugh at me for loving this car way too much, and they will be happy to do it all over again. What the speedo shop will find, is another question entirely.

-Sean

 

^^^^^ So true unless you can't wrench at all and then $300.00 is a deal to have anything done on these cars.



^^^^^ A non functioning ODO may cause questions at sale time but a functioning one is no guarantee of mileage.

I would have at it following the write-up by Dwayne and others and see what you find.

 

It's not selling the car that concerns me, it is appraised value. This is the basis on which I get insurance. And as long as I get the odometer working with realistic mileage, the appraiser doesn't need to know that it wasn't always working.

-Sean

 

OK, back on this,

I read in another thread that odometer problems can include a tiny drive motor and a chip for that? Are these parts even available? I'm going to chat with Palo Alto Speedometer about this.

-Sean

 

I did'nt know Dwayne did a odo write up. Pretty amazing stuff.

 

Here,s Dwayne,s superb write up

http://dwaynesgarage.norcal928.org/1...0Procedure.htm

Ken
80 928 S
5 Speed

UK

 

Alrighty now,

finally had the console shipped back to Palo Alto Speedometer. Today they informed me that this time the "pot metal drive on the other side" opposite the main drive gear had fallen apart, so they replaced it. While they were at it they decided to replace my aftermarket drive gear with an original gear, because their experience has shown that the aftermarket gears cause the whole set to bind up more easily.

So yes indeed, my odometer broke in two different ways within a few months. With any luck, *now* it can last for 100,000 miles?

 

I found the entire line of gears and numbers was lose on the shaft. A quick fix was fashioning a fiber washer to slide on the shaft on the left side. This keeps pressure on all the digits to make sure they never lose contact and keep turning...

 

Interesting "replaced with an original gear" if it existed we would all be selling it I can assure you.
It does not exist so we have to use the AM version.