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speedo cable

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jvandyke

jvandyke

Luke Skywalker
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I'm having trouble convincing my speedo to work again. Cable was rerouted and speedo relocated recently (to correct positions). Needle did not budge. Pulled over and detached cable just reaching up under there, drove forward a few feet just to see if the cable spun, it did. Reattached and it indicated erratic speed. Is there a trick to this or is something inside not happy?
 
Does the odometer work? If it does, that proves that things are moving inside the speedometer box. The odo is hard-connected to the input shaft, but the pointer isn't; it's moved magnetically.

If the cable is turning, it's gotta be something like a stuck pointer. I suppose that the shaft inside the speedometer could be broken, but it seems unlikely. There really isn't much else that can go wrong.

The shaft that moves the pointer is pretty delicate, as are the pivots it rides on. It's at the center of an aluminum cup, more like a disk, which provides lots of opportunity to bind somewhere. The slightest amount of extra crud can do that--one visit by an indiscrete mosquito is probably enough.
 
The odometer wasn't working either, until the point where I had erroneous needle movement, then it did too. I took cable off, put it back. We'll see how it goes. It did work fine, though was always off by 5 mph. I thought maybe cable was binding somewhere but it shouldn't be now that it is routed "correctly"....I think.
 
I wonder if it has a kink from being routed incorrectly? you might also be able to lube the cable some
 
Maybe. It comes up from the gearbox heading towards the front, a big loop back and through the hole in footwell next to where the steering column goes through. It was spinning fine when I held it in my hand and moved slowly. I'm pretty sure it's the speedo itself, these are the "eddy current" variety I assume? Delicate little monsters. I rebuilt one once (in an Opel) and it was a pain. I think it needs a good extended run through the country side.....don't we all?
 
I have seen many speedometers that didn't turn very well at all!
I usually just take them out, put them face-down on the table and put a drop or two of 3-in-1 oil on the input spud (?) and turn the speedo with a 16 penny nail until it turns freely. It usually just takes 5 or 10 turns to work the oil into the bushing and free up the works.
Never had a speedo failure after I did that.
BillM
 
Awesome, if it's still grumpy I'll give that a go.
 
I'm stumped. Removed speedo and on the bench it's fine (using a bit of square cable chocked in my drill). On car, no go. I know the cable is spinning when the car moves. What could this mean? End of the cable still looks good and square to me. Weird? Maybe wrong cable and when I rerouted it won't work? I don't think so. I'm thinking a small spacer behind the stop....at least they're not expensive...if that's the problem.
 

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Should I be able to pull the inner cable out of the casing? It slides right out. I assumed it was just "press fit" into the gearbox, you know the two ends of the casing are attached while the cable itself is just sandwiched in there. If not, maybe the cable is broken...but it spins....
 
It should pull out easily. The cable just fits into a square hole in the drive gear in a manner similar to the speedometer body. It's easy, however, to think you have it all the way into the drive gear when it isn't; it only goes in something like 3/8" if I remember correctly.

Both ends should be square in cross section, about 1/8". Are you sure the one at the speedo end isn't rounded off or something like that?
 
I added a little spacer and I cut off just a bit of the end that goes into the speedo as it was rounded off ever so slightly. Speedo works now. Then I went to pull the cable back out as I thought I should grease the snot out of the spacer I added and the cable didn't want to come out of the casing. I packed grease in the end and reattached. Hopefully it still works tomorrow.
 
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