rubbing or burning speedometer cable

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MrBlimp
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rubbing or burning speedometer cable

Post by MrBlimp » Tue Oct 09, 2018 12:02 pm

When I got my 78 124 it was sans speedometer cable. I purchased a new one (snap onto back of speedometer not screw on), but had some issue with the internal cable not being long enough. Either that or it was because of the routing.

Regardless, once installed the cable wasn't working. So I bought a universal one that would allow me to cut it to the exact length required. Before I could install it the speedometer started working with the one that came in the new cable as if it finally self seated itself.

After a few hundred miles it stopped again. So I figured the shortness of the cable allowed it to unseat.

When I pulled it out I found it had snapped clean about 10 inches in from the gauge. I checked the outer cable and found that that about 3 inches of the exterior coating was gone and the internal metal wrap was badly damaged.

I've ordered a new one but am questioning how this could have occurred. Could there be something rubbing (like the steering column) or maybe some slight kink stressed the inner cable creating friction, heating it up, and melting the outer cover and metal wrapping. I think had that occurred I would have smelt something from the outer cable.

Thoughts?
1969 Triumph Spitfire
1970 MGB
1978 FIAT 124 Spider
1992 Mustang LX
2000 Jeep Wrangler Sport
2000 Ford Rangler XLT
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bartigue
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Re: rubbing or burning speedometer cable

Post by bartigue » Wed Oct 10, 2018 4:26 pm

This usually occurs because your motor is not grounded to the body well enough and electricity starts to find better grounds, the clutch and speedometer cable being the easy targets. When you replace the cable inspect and replace the battery to body ground and the engine to body ground. Doesn't hurt to add a transmission bell housing to body ground.
-----------------------------------------------------------
Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
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