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Speedometer Issues

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  • Speedometer Issues

    I just rebuilt it and rolled back the odometer to 99999. I hear a clicking sound that speeds up along with the car, the speedometer fluctuates terribly, and the odometer doesn't work.

    What's up with it?

  • #2
    Are you using a new cable. My first thought is that the end of the cable is worn or not pushed into the speedometer all the way.

    John Pizzi - Squarebirds Administrator

    Thunderbird Registry #36223 856-779-9695


    • #3
      No I'm using the original cable. I took it apart, cleaned and inspected it and it looked in very good shape, then I lubricated it and reassembled it.

      I think I may have locked-up the odometer when I turned it back to zero. Actually I turned it to 99999 and figured it would just roll over.

      I think what's happening is the cable spins at transmission speed and activates the speedometer, then something binds in the odometer, then something in it "clicks" as it refuses to move. The wild behavior of the speedo must be the cable being torqued then released cyclically.


      • #4
        Yeah it was hung up somehow. I reset it using the technique described in our technical library and it works perfectly now. I tested it with a cordless drill and a #2 square drive bit, "driving" it 2 miles.

        While I had the gauges out I replaced the high beam indicator bulb with the dimmest one I could find, and figured out why the gas gauge wasn't working (wires reversed).


        • #5
          It hung up again at 99.9 miles half way to my trip to the NC mountains. I stopped at a repair shop and had them cut the cable so I could drive on without that blasted clicking!


          • #6
            Does anyone know a shop that repairs or sells reconditioned odometers?


            • #7
              Yeah, I believe our TRL shows places that recondition gauges.

              Oh BTW, your OEM gauges are NOT polarity specific. They work with the heat from current.
              My latest project:
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              "We've got to pause and ask ourselves: How much clean air do we need?"
              --Lee Iacocca


              • #8
                An update on this, I found a gauge set on ebay and bought it for the odometer. The drive gears were all gummed up when I took the set apart, and the odometer itself was difficult to turn. More so when flipping to a ten digit, even more to 100, and so on. The plastic digit cylinders are separated by thin steel separators; my theory here is that the steel-plastic interface is gummed up or corroded, so the nylon drive gears can't turn it over to a new digit.

                I did not want to take it apart as I had so much problem with my original when I did that. So I cleaned it up with a water based "all surface" cleaner (similar to Windex but very gentle). I saturated the outside with spray and scrubbed it all over with an old toothbrush. I used those green dental picks sold instead of dental floss to get all between the disks and metal separators. Then rinsed it thoroughly with warm water, then used compressed air to dry it all out, blasting air between the disks.

                I then used a lubricant that is used for my laser plotter, compatible with plastic and steel, and coated all the interface surfaces and down between the discs. Then I spun the mechanism by hand while watching television. The 100 changeover got easier the more I spun, then difficult at 1000, so I added more lubricant and worked it forward and backward until the 1000 changeover became easier. The next 1000 was easier, and so on.

                Not wanting to watch TV for several hours, I cleaned up the old worm gear and rigged that up with a drill bit extension and spun the mechanism using a power drill, stopping short at a 10,000 changeover. I turned that by hand, again finding it had to be forced, adding lubricant, then working back and forth.

                Since I started with an odometer reading 91,000 I now have one that reads just past zero. I'll install it and hopefully won't have an issue a few years from now when it reaches 9,999.9...

                Hopefully the mechanism is freed up