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Tach


Milt
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My tach started freaking out recently too, I suspect a ground problem. You

might check to make sure that it has a good ground. Its also possible that

our tachs are just getting to their replacement time. The faces on both my

speedo and the tach are showing age, I think I will eventually get new S&W

gauges to replace them. Unfortunately, when I did that on my Hawk, the

gauge housing was a slightly smaller diameter on the new S&W gauge from

the old S&W gauge. It still fit "ok" but wasnt tight in the dash hole.

Tom

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It could also be the sending unit which is located under the dash behind the gauges. Check all the connections but the sending unit could still need rebuilding or replacement. Check with Stewart Warner and see if they have a trouble shooting procedure to determine the problem.

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  • 4 weeks later...

The tach on my car does not work. The needle is stuck at 2500 RPM. The previous owner noted that the needle just stayed where it was one day when he slowed to a traffic light.

Is the problem likely mechanical or electrical? Is the tach easily removed (without removing the whole dash) for repair? Would a speedometer shop be able to work on an aged unit like this? If so, would it cost a fortune?

I've ignored it for the past four years, but it would be nice to have a working tach. The clock doesn't work either, but then I don't think I've ever seen a mechanical clock in a 1960's car working anyway.

Any advice would be appreciated.

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If you have small hands, and drop the steering column, you can remove the tach. It's tight, but can be done. There is also the sending unit attached under the dash. That's the electronic part which could well need rebuilding. Depending on when your car was assembled, it is either a flat, round can with wires attached, or a squarish plastic unit.

No telling what the problem may be, but both parts are rebuildable. I believe the guages were supplied by Stewart Warner...maybe they can rebuild them. There are specialty rebuilders that can do it as well. I'm not sure, but somewhere I've seen a schematic to rebuld the sending unit...maybe in a back isue of the AOAI newsmagazine. Maybe someone else here can clue you in on that.

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Thanks for the tips. My hands are small.. I'll see what I can do to remove the units for servicing. Is the steering column easily "dropped" by removal of a bracket or is it more involved than that?

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It's pretty straightforward dropping the steering column. If you have the shop manual it gives the instructions. It's only a few bolts.

If you have a steering wheel puller, it would help to remove the steering wheel (and unbolt the driver's seat...makes for much more working room).

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  • 8 years later...

If your brave enought to peel the bezel back and dis-assemble the gauge, sometimes a bit of 3-in-1 oil on the shaft supports will free up a 'gummy' tach which is otherwise fine.....You can also take this oppurtunity to refinish the needle, which, no doubt, has faded over fifty years.

(Of course, if you do re paint the tach needle, you'll have to do the same to all the other gauges!)

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I agree with the oil. The old grease dries up and the needle doesn't swing properly. I converted one to modern internals a couple years ago and the process is on Bob Johnsons tech site that can be accessed through the resources tab on the home page. This eliminates the sending unit.

Rob

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