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Speedometer Leak

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Old 03-08-2019, 07:55 PM
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BlueL82
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Default Speedometer Leak

Well I put in a new bullet and cable but still have a leak. What am I missing? By the looks of things it's leaking from the cable itself not the threads. Pic attached. (1980 w/ Th350)


I still have the box for the cable. Should I return it and get a new one?

Last edited by BlueL82; 03-08-2019 at 07:56 PM.
Old 03-08-2019, 08:29 PM
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0Willcox Corvette
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The coupling you are screwing the cable into has a seal that can be replaced. Did you replace it? (it's pictured in the lower part of this post)... they tend to dry out and leak... Then there is the 0-ring on the actual fitting.... did you replace this. I highly doubt the cable is the issue, it's typically one of the two seals and my advice is to fix it as soon as possible. The speedo cable is reverse wound and this will pull this oil into the speedometer head. The first worm and magnet bushing is made from what is called Oyl-lite which is a oil impregnated brass bushing... guess what they don't like.... OIL....

The oil is pushed up the cable and into the first worm and magnet, then considering the magnetic field generated by the first worm magnet... .it attracts dust and other particles in the air and will cause the speedometer head to prematurely fail.... IMHO....

If you have not replaced both, you should.

There are actually two seals, one is the o-ring around the fitting and the other is fitted into the end of the fitting you are screwing the cable into. You can see the o-ring in the picture below. We have the o-ring at this link but I don't think we have the end seal on the site... I'll have to check or you can give Tommy a call on Monday at 812-288-7103 and he can fix you up. I'm sure we have both on the shelf. Oh... never mind.. I found both.

Seal for the fitting https://willcoxcorvette.com/corvette...seal-1958-1982
O-ring seal https://willcoxcorvette.com/corvette...diameter-55-82

I'd still call it in, we're having issues with the site on the USPS shipping option and Tommy can ship both pretty cheap if you call it in.

Willcox





This is the fitting seal.


Last edited by Willcox Corvette; 03-08-2019 at 08:32 PM.
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BlueL82 (03-16-2019)
Old 03-08-2019, 11:39 PM
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7T1vette
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The speedo cable is bundled wire formed in a spiral fashion. As it rotates, any oil leaking thru the speedo "bullet" (see pic above) will be "screwed" by the spiral wire up to the speedometer. You need to fix the bad/worn/old O-rings in the 'bullet". Then your problem will disappear.
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Old 03-16-2019, 01:47 PM
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BlueL82
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Solved! I saw a video online recommending that you tap the inner seal in further. Going to try it later and hopefully get the vette on the road this weekend!

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