68 Speedometer Not Working

[oldlefty]

Speedometer on my 68 912 isn't working. Car has been apart for 30 years, it worked when I parked it. I went through all my instruments over the winter, just cleaning up the faces and the inside of the glass. When I got everything back together and started some test drives the speedometer needle never moved- although the odometer and trip counter work.

I assumed the needle was frozen after 30 years so I took it apart again and once I got it apart found that the needle floats just fine with just a hint of a push- no sticking or breaking loose. What's more, if I take the trip counter cable and stick the square end of that into the speedometer input hole, the needle moves just fine when I spin it by hand.

I took it apart again and got the magnet drive shaft out, cleaned and greased it, put everything back together, checked again that I could get the needle to move by spinning the reset cable in there, worked fine. Put it back in, took it out for a drive- nothing???

I'm baffled. The odometer is gear driven off the same shaft, it is working fine. The needle moves when I spin the input manually on the bench. But in the car, driven by the speedometer cable, the odometer works but the speedometer needle is dead.

Any ideas?

[1QuickS]

Send it to Palo Alto Speedo.

[oldlefty]

Send it to Palo Alto Speedo.

Found it. The speedo was fine, it was the cable. The square inner cable stuck out about 10mm from the ferule- it's only supposed to stick out about 1.5mm. I put it back together but only screwed the cable on a thread or two and now the needle is moving. With it screwed in tight the inner cable is pushing too hard against the shaft and binding it up enough to interfere with the rotation of the magnet. I'll need to "take a little off the top" of the inner cable.