Speedo bounce

[micbrody]

When I bought car, speedometer would intermittently work. Eventually after 100 miles, total failure. Upon inspection, I needed a new cable.
Installed new cable, but square hole in speedometer must have been rounded, because I, again, would have intermittent function.
I jammed wire in with tiny sliver of copper, to "permanently" keep wire attached to round hole. This worked great. Everything worked; a very tiny amount of bounce at low speeds.
Over last few weeks, the tiny bounces became huge bounces. I inspected "permanent" connection. It was intact. I removed speedometer and cable, and cleaned sheath and cable; and lubricated. Re-installed. Still large bounce. I disconnected from speedo drive gear side , attached drill to wire, and saw speedometer work flawlessly.
I concluded that square end must not be seated well in drive side. I tried to wedge a thin filament of wire in hole and re-attach cable. I worked great....perfect. No bounce.
A few days later, a very tiny bounce re-appeared. I figured that the thin filament must have weakened in connection, and that there was a little play. This time, I disconnected, used some epoxy down the hole, and re-attached.
Now it still has some bounce; and cable is firmly attached (I cannot pull out cable).
Question: where is the bounce coming from? Do I need a new speedo drive gear? If so, can I install easily with transmission in car?

[baltobernie]

... can I install easily with transmission in car?

No.

[micbrody]

Any other possible things to try without changing speedo drive gear?

[baltobernie]

I don't know. It sounds like you had a restriction in the speedo drive somewhere, and that buggered the cable end at the instrument. What's troubling is that even when you secure it at the instrument, the restriction reappears shortly thereafter. That seems to indicate the problem is now on the drive end or the instrument itself.

Maybe the restriction was caused by a bad cable, and the drive receptacle is rounded also? If you are committed to resolving the problem, I suppose you could epoxy the cable end in to the drive receptacle. If it doesn't work, you're no worse off ... you'll have to drop the transmission anyway. I might try swapping instruments before resorting to epoxy. (unless you're due for a new clutch, anyway )

[micbrody]

One thought that just dawned on me. Without any pressure, the metal outside part of cable does not lay flush with the receiver part of speedo driver. Maybe when I tighten the cable nun down , it causes a little flex in inside cable. If flexed or bent, maybe that could explain issue.
When I have a chance I will significantly loosen the nut . See what happens. Nothing to lose

[DieselSpider]

If you wedged a sliver of metal in the cables drive sockets at either end of the cable you now have it spinning out of balance and its only a matter of time before additional collateral damage shows up. If the speedometers drive socket is rounded or egged out then its possible that the start of your troubles was a speedometer that had too much drag and was stressing the cable along with the speedometer drive in the transmission. The speedometer probably at the least needs cleaning to get rid of the stray particles from to worn drive socket out of it and lubricating along with a new drive socket installed in it and potentially the speedometer drive in the transmission may now need replacing.

Epoxy does not always stay put and is a poor lubricant as it starts flaking or chipping off so any epoxy dust that gets into the speedometer drive is just another potential failure point.

Some I have noted also cause speedometer issues when routing a new cable as they set it too close to the exhaust system causing it to get heat damaged or from bending it to sharply. Sometimes rotating the cable 180 degrees to get the stressed area on the outside of the bends where the inner cable rubs as it spins shifted to a new area can help.

[micbrody]

The speedometer could be gummed up with oil. When I removed "original?" Cable, there was a lot out brown, thick oily sludge in cable tha did make it to connection of speedometer.
How do I disassemble and clean speedometer?

[micbrody]

update:

I disconnected cable from speedo driver . When re-attaching, the wire does not go all the way in (probably from previous thin shimming wire being pushed to bottom of hole. when I insert square cable, it left about a 2 mm gap between the outside metal end of cable to the end of the driver. This time, I just tightened the speedo cable a little (so not to cause flexion of internal square cable), and applied locktight so the outer nut would not vibrate loose.

When I went for drive, everything perfect..............
I drove it on highway today about 30 miles each way; topped out speedometer to 85 a few times.
Everything was great; however, when I got off highway, and close to house, I noticed a speed related clicking noise (very subtle, but definitely new). Though I can't be certain, I think it was coming from the speedometer.

Another "interesting observation" about speedometer. Before today, before starting car, speedometer would read between the 0 and 5 MPH (3 ish MPH). When I would back out of drive way, it would deflect to under 0. And then when I started forward everything would be fine; with speedometer returning to the 3 ish MPH at stop lights. After driving 30 miles at high speeds, I got off highway and speedometer only went down to 8 ish MPH at stop light.

Last observation: at 80 MPH, there was some tiny bouncing of needle. No bouncing at normal speeds.


Conclusions of the previous observations: Something screwed up in speedometer. I think I will probably try to open it. Any help/pictures/instruction would be appreciated!

[Texsardo]

I have a speedo if you want. Worked when taken out. $30 + postage.
Texsardo