Speedo Needle Jumps

[Z71 GMC]

After installing white face gauges on my 99 sierra my speedo needle jumps up when i accelerate rather than smoothly moving up. The new gauge face isn't glued on like the old and I dont know if the needle is rubbing on the new gauge face or what. Please help! thanks.

[bill190]

I just had the same problem today after working on a car instrument cluster (non-GM), anyway suddenly the needle bounces back and forth.

 

I was searching for the cause of this on the internet and read something about there being a "damping fluid" inside some speedometers and it said you should not turn them upside down when working on them because the fluid will leak out or some such thing.

 

Well I did turn my instrument cluster upside down and every which way while working on it. So maybe that is the problem?

 

But I didn't see any fluid leaking out????

 

I don't know if this is in fact the problem or not.

 

Another theory I have is my screwdriver is magnetic and I used this to unscrew the speedometer screws. I don't know if this might have caused the problem???

 

Anyway if anyone knows more about this fluid thing, is there a fix?

 

I read my service manuals tonight and see if it says anything about this problem...

[bill190]

Well I just looked at two factory service manuals - one for a 95 Ford and one for a 92 GM.

 

Neither book said anything about the needle moving back and forth, nor did they say anything about any fluid being in the speedometer, nor were there any warnings about not turning the instrument cluster upside down!

 

All they had for service problems were noise from the speedometer, accuracy, or not working at all.

 

The Ford was a mechanical speedometer, the GM electronic although with a dial like a mechanical speedometer.

 

I'm getting the impression there are all sorts of different kinds of speedometers out there! (Including what I read on the internet.)