[Oli]

Looks like all the gears are intact, except I cannot see underneath the gear connected to the speedometer cable. It might be stripped. I just don't know how to remove it and it appears the brass fitting is holding it in place.

[Richard Curtis]

there is a write-up on this somewhere, maybe a 964 forum on Rennlist. Search is your friend.

[Oli]

Originally Posted by Richard Curtis

there is a write-up on this somewhere, maybe a 964 forum on Rennlist. Search is your friend.

This is for a 76 mechanic operated speedometer, so the 964 is electronically operated.

[Trak Ratt]

Originally Posted by Oli

This is for a 76 mechanic operated speedometer, so the 964 is electronically operated.

Both true, though IIRC the gears pictured drive the odometer, not the speedometer


Most of the gears turn to mush after a few decades. There is a guy that reproduces the gears AND has DYI instructions on his site.

Edit" easier to find than I remembered; http://www.odometergears.com/documen...eplacement.pdf

BTW, how about adding a name to your sig. and maybe provide an intro here; https://dorkiphus.net/porsche/showthread.php?t=13610

[hoophead]

I've done a few of these old mechanical speedos before - the problem was typically a pot metal gear that was supposed to be pressed onto a shaft, but now spun freely. Roughing up the shaft with some pliers and pressing the gear back on was the fix.

Hard part of all of this is getting the stupid bezel off the gauge so you can dissect it.

[Oli]

Originally Posted by hoophead

I've done a few of these old mechanical speedos before - the problem was typically a pot metal gear that was supposed to be pressed onto a shaft, but now spun freely. Roughing up the shaft with some pliers and pressing the gear back on was the fix.

Hard part of all of this is getting the stupid bezel off the gauge so you can dissect it.

So, correct me if I am misunderstanding you, are you saying to take a pair of pliers and muscle those gears out? Could I not do the same thing with a small screw driver and lodge it underneath the gears and pry it up and out?

[hoophead]

No - the gear slides right off the shaft on its own. That's the problem. You take the pliers and grip the shaft where the gear previously sat, then rotate the shaft in the grip of the pliers. Basically you want to rough up the surface. Then you slide the gear back on over the roughened area and it should not rotate any more.

You should be able to turn the speedo input drive gear or one of the closer reduced gears and see how the shaft spins but nothing happens because the gear in question slips (I think I have that straight) - then you will understand the problem.

Sorry I don't have any pictures - it was a long time ago before digital cameras.

[hoophead]

Look at this link: https://www.pelicanparts.com/techart...ter_Repair.htm

I'm describing the second failure mode.