Speedo Worm Drive

[HMeeder]

Ok, so I repair the pot metal gear on the odometer (like PP's article said, it was spinning on the shaft.) Seems like everything should be fine, but now the worm drive that comes off the speedo cable shaft (and drive the odometer)isn't spinning. I pulled the speedo thing apart (where the magnet and bell are) and I noticed that the worm gear that comes off perpendicular to the shaft has some play in it. If I pull the worm gear out a bit, it catches on the shaft and will spin. Let the worm drive drop back into it's natural position and it ceases to turn. So, it must be either stripped (either the speedo shaft or the worm drive) or (as seems likely) the gear must be out of position. On the oposite side of the worm drive there is a plug that apparently keeps the drive in its place. Question; Would driving it further in eliminate the play and put it back in its correct position or would I just screw the thing up beyond all fixing??

Herb

[sammyg2]

Pull the speedo right angle drive out of the tranny and use a flash light to look inside the hole (watch out for oil). There should be a brass gear coming off the tail of the output shaft. It should be secure and not stripped. Next, look for the bushing that the angle gear bottoms out against. It is pressed into the rear cover. Problems with either one of these could keep your speedo from working.

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Gerald Gore II (Sam)
73 914 350 small block

[Dave at Pelican Parts]

Wrong end of the cable, Sammy. I think he's talking about the bits that are inside the speedometer.

It's been long enough ago that I tore my speedo apart that I don't really remember enough to answer the question.

--DD

[sammyg2]

Oops. Sorry bout that.

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Gerald Gore II (Sam)
73 914 350 small block

[HMeeder]

Sammy; Dave's right, I was talking about the other end (speedometer internals.) Sorry if I wasn't clear about that.

I sat and ruminated about that wormn gear for quite a while and the more I thought about it, the more it seemed obvious that the gear was out of position relative to the speedo shaft. By lightly tapping the "plug" further in (used a 7mm socket and hamme), I eliminated the play in the worm gear and set it back into position.

The gear now has about 1-2 mm of drift in and out (didn't want to bind it up) and the worm gear that drives the odo spins just fine. Put everything back together and the speedo and odo are working perfectly.

I just needed the guts to pound on a finely crafted German instrument with a hammer and only a bit of common sense to guide me.

Herb

[HMeeder]

Sammy; Dave's right, I was talking about the other end (speedometer internals.) Sorry if I wasn't clear about that.

I sat and ruminated about that wormn gear for quite a while and the more I thought about it, the more it seemed obvious that the gear was out of position relative to the speedo shaft. By lightly tapping the "plug" further in (used a 7mm socket and hamme), I eliminated the play in the worm gear and set it back into position.

The gear now has about 1-2 mm of drift in and out (didn't want to bind it up) and the worm gear that drives the odo spins just fine. Put everything back together and the speedo and odo are working perfectly.

I just needed the guts to pound on a finely crafted German instrument with a hammer and only a bit of common sense to guide me.

Herb