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Odometer repair?

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I've searched all the forums and read many posts on various speedometer and odometer failures (across the many LBCs). It would seem that my main odometer ('59 Sprite) is not working... but the trip odometer is working fine (as is the speedo itself).

I'll be pulling it and snooping around, but my question pertains to the possibility of tweaking this puppy myself. How does the main odo go but not the trip one? I realize that they probably have their own drives, but what gives? Is there a common shaft with differing gears for the two odos?

Does anyone have a photo of the interior or any advice in this regard? I've only seen photos of the guts of a speedo from a later Sprite.

I've been known to tinker with the internal workings of gauges (and have had some luck with the magnets, coils and delicate wires in an early fuel gauge) so I'm not squeamish about that. :yesnod: On the other hand, I do have a shop here in Portland that does Smiths repairs (that I've used before)... but would like to avoid that step if I can.

Yeah yeah, I know what you're thinkin'... "count yourself lucky the trip odo works." Still, is this something I might be able to fix myself?
Thanks.
 
All I know is springs fly everywhere, that all I know!
Been there tried to do that, own 3 now and none of them work!

Had to tear one apart because my E-Bay seller put it back togehter wrong by putting the high beam light tube out the back of the case, springs, springs lots of springs.

Mark
 
Hmmm... springs. Not good. Sounds tricky. Looks like it might be mini-clock work. Didn't find too many relevant webpages (except https://www.spridgetguru.com/TA0005.html and https://www.expeditionlandrover.info/2trSite/PDFs/speedo.pdf). Found this image but don't think it applies since I don't see the trip odometer as part of it. My hunch is that some gears are disengaged (or damaged/worn). :frown: May need to live with a recycling trip odo until I have someone repair it.
Still, if anyone has any photos, please forward.
Thanks.
 

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Plastic or fiber gears are usually stripped because the mechanisim has gotten gummed up over time. Probably best to send it to some one with parts.

Kurt.
 
Thanks Kurt.
 
The picture Mark posted was for a chronometric speedo/odo. That is very different from what you will find in your '59. However, the second link he posted was the Anthony Rhodes document for the traditional Smiths speedo/odo that you will find in most of our LBCs. I strongly encourage you to print out the PDF and read it before working on your odometer. Work in a clean place, well lit, with a white cloth covering the entire area where you are working. That will help you keep track of the parts and not loose anything. Use a camera and a sketch pad to take notes and record the disassembly steps.

It may not be the fiber gears that have failed. The other equally common failure mode is wear of the pawl that is moved by the fiber gears. The pawl pushes a toothed gear on the odo shaft. It is not uncommon for the sharp leading edge of the pawl to wear into a notched shape. Some gentle, minimal filing of the pawl can restore it if you are careful. Some of the odo pawls have light springs to hold them against the toothed wheel. If the spring has popped of the odo will not work.
 
Thanks Doug! Great advice. Yes, I thought maybe the pic wasn't right (but that the PDF had lots of good references to "early" speedos). Thanks for the details on a possible repair.

Although I haven't opened it up yet, this photo (from the PDF file) might be what I have. I am hoping that there is a simple fix (given that the trip odo works), but hope springs eternal. :yesnod:
 

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It's been a while since I opened one of these, but that picture looks familiar. If you just take the case off it, I think you'll see right away how it all works. The problem might be something simple--in fact, if the trip odo is working, I'll say it probably is something simple. Like, as Doug mentions, simply a spring has come off.

Worst case, you can find speedometers on ebay for not too much $$.
 
Very true. As far as the odometers go, donor parts from any similar looking speedometer are likely to work regardless of whether it is from an MG, Triumph, or something else. A junky looking speedo on eBay would likely supply most if not all of the donor parts you might need.
 
Well, I agree that it doesn't hurt open it up and see if you can find the problem. May be a simple fix. The one in my MGB simply stopped working cause turning over 100K stripped the gears. once I manually turned it over and lubed it the gears were still good enough that it was working when I sold the car at 105K.

Kurt.
 
Thanks all. Yes, if I have to pull it out, then I might as well take a peek and see if it is something simple. If not, maybe a donor might be the way to go. Much appreciated for all comments.
 
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