Confirm source of broken odometer?

[Doug&Julie]

My odometer is broken on my recently purchased 911T. I bought the car knowing the mileage was not accurate and the odometer worked "intermittantly", but since I picked the car up, it has stopped working completely.

My question is what other possible causes could the failure be if it's not the "Broken Gear Syndrome"?

The reason I ask is would intermittant operation be a sign of BGS or something else? Also, I can turn the trip odo and it will crank both the trip odo and the main odo. Is this normal?

If this is simply BGS than I can easily pull the speedometer and send it off to North Hollywood or something. But I don't want to send a perfectly good speedometer if it's something else?

By the way, the speedo part works just fine, as do ALL of my other gauges.

Oh, and I did a search here and found out a lot about changing out your own gear, but nothing on other possible causes of odo failure....thus this post on a common topic.

Thanks.

[Doug&Julie]

Nobody has any other thoughts? So it's for sure the odometer then?

[sammyg2]

I'd say the odds are very good that it is BGS.
In fact I'd bet your next paycheck that is the problem

[Miguel Antonett]

If that bothers you, send it to North Hollywood; for $125 they'll fix it regardless of what's wrong with it. My opinion, leave it alone and enjoy the car.

[azasadny]

North Hollywood fixed my speedometer over a year ago and it's been perfect since. Very reasonable and fast!

[Doug&Julie]

Originally posted by Miguel Antonett
If that bothers you...

It doesn't so much bother me as I'm anal and need a gauge to monitor my service intervals with. ..not to mention keeping accurate records.

Thanks all, looks like I'm pulling the speedo this weekend!

[project 911]

Doug-

I went through this with my 71. It seems to be different than what I see everyone else talking about as it has no plastic gear. It has a potmetal gear to the right of the odometer number wheels that is pressed onto the shaft. That gear gets loose on the shaft causing it to slip and also letting the shaft slide sideways so a small gear at the end dissengages.
I opened mine up, left the face and needle in place. I taped the number wheels together and removed the shaft and potmetal gear. I used a center punch and made three hits with it around the center hole of the gear (be carefull). I then tapped the gear back on the shaft and put it all back together. I did have some trouble getting the trip odometer engaged properly, but it all works now. Mine was doing like yours was. Sometimes it would go, most times it wouldn't.

[Doug&Julie]

Thanks Steve. I'm not sure I'm comfortable taking my gauge apart myself, so I'll probably just stick with the NH plan. But it's good to know what's going on inside so I won't sound like an idiot when I talk to them! (...ok, I can still pull that part off )

Thanks again,

[project 911]

Don't blame you a bit Doug. It wasn't the most fun thing I've done, and pretty easy to screw something up. It is annoying to not have any idea what the actual mileage is...

[island911]

A broken gear will more than likely just simply stop working. (so I doubt its that)

I just fixed a VDO out of an old Mercedes. (very similar to an older 911)

There is a primary drive wheel, which is pressed on to the shaft, for the Number cluster. (it slips . . this is the same one Steve is talking about)

Obviously, I feel fine taking these things apart. They're not rocket surgery; as Tyson would say. All you have to do is really examine the assembly . .understand the assembly, before taking it apart. Follow Steves fix w /the punch.

[island911]

This is the gear (of sorts) which I'm betting is slipping. (pot metal)


this is a MBz clock.

it could be one of the others slipping.

[84porsche]

I also have the same problem and suspect its the odometer gear as the speedo still works fine. I just find it difficult to be without my car for a period of time in which it takes to fix it. The bad thing is that I can't compete for the highest mileage 911 anymore.

[island911]

84, for new speedo's / odo's, see Odometer Gear replacement for Electronic Speedometers (long)