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Speedometer/odometer questions

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John_Mc

John_Mc

Jedi Knight
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Rather than continue to usurp Paul's gauge thread, I'll start a new one.
I have my gauges out of the dash. My speedometer had not worked in a year. I discovered by sticking a screwdriver in where the cable attaches that the speedometer was just sticking. It's free now but I still feel resistance. Anyway to determine how much resistance is normal? Where and with what do you lube the speedometer? Also, I have a trip reset cable that came with the car but was never attached. The end that attaches looks like a threaded cable while the knob on the odometer looks sorta like a slightly oblong flattened hex pin. How do those connect and what action resets the trip counter? I couldn't get it to reset manually. Thanks for any and all feedback.
odometer-1.jpg
 
Should be almost no resistance at all; if you can feel anything at all then IMO it's too stiff. My feeling is that once it's gotten stiff, it likely needs to be replaced. But you can try adding a very small amount of light machine oil (eg 3-in-1) to the boundary between the input shaft and it's housing. Spin the input until it frees up (or you get tired and give up).

There's a good article posted at
https://home.comcast.net/~rhodes/speedo.html
with more details, including a possible means of disassembling the input bearing to lubricate it.

Sounds to me like you either have parts missing, or have a mismatched speedo & reset cable. Not certain but I think 71 was the transition year between the threaded connection and "twist to lock" style.
 
A little lubricant seems to alleviate the resistance I was feeling. Another problem I'm encountering is that foolishly I didn't record the sequence of pieces of the trip odometer as I took it apart, thinking the Rhodes Speedo article would explain it. But now I can't figure out where the spring goes. It's not listed on the "intermediate" speedo diagram, and the "late" model, according to the author, is essentially the same as the intermediate but in a different frame. Anyone have any idea where that spring goes??? :wall:
 
If you mean the spring that is about 5/8ths of an inch long (more or less) with a loop on each end -- then it is what tensions the pawl against the notched end and advances the odo incrementally.

Don't have one in front of me but IIRC one end hooks on the arm of the pawl and the other on a little hook down in the innards of the unit -- possibly a hook that is stamped out of the metal frame.

I usually loop a length of dental floss thru one end of the spring then fish the spring down in the unit and get it to catch on the hook. The dental floss can then be used to stretch the spring over the connection on the pawl. Once it is in place (3 tries is par) clip the dental floss and slip it out from under the spring loop.
 
Geo,
The pawl spring I have in place okay. It's the silver spring in the pic below that confuses me. It either goes inside or outside of the white notched wheel OR it could also go outside of the black gear wheel. I've tried all ways and I still can't get the trip odometer to reset. If I can determine which is correct, then I can address the next suspect area which is where the notch on that white wheel comes to rest.
odometer003-1.jpg
 
Through trial and error and careful scrutiny of enlarged pictures from the Rhodes article, I've concluded that the spring goes outside of the black gear wheel. I've been able to get the trip reset to work, although it appears that the action would be the opposite direction as described in the bentley manual. When all is said and done, however, without a proper trip reset cable, the trip odometer is of no use. :frown:
 
John,
I discovered that the drive spindle of the speedo had a small bit of aluminum from the housing causing it to bind up. This required complete disassembly but it revealed the source of the binding. Could that be the problem?

Terry
 
I have a question on the odometer and its connection to the mph reading. The car I am working on is a tr3 but there must be some kinda of connection. Anyways, I had a floating and bouncing needle on the gauge and when I would reset the trip odometer the needle would flicker. I thought that is interesting. So I am thinking the odometer is sticking a little and that is being transferred to the needle. I mean they got to be connected somehow and when I saw your picture of the odometer taken apart, I thought perhaps a good cleaning of the odometer might free up my needle also. How hard was it to get the odometer apart? And am I in right field again.
 
Google for the Anthony Rhodes PDF speedometer article and it will show how the odometer and speedometer work together.

I suspect that somehow when the trip reset was actuated it briefly changed the position of the worm gear a bit or restricted its motion causing the flicker you observed.
 
sp53,
The link to the Rhodes Smiths/Jaeger speedometer repair manual is on the previous page in Brosky's post. It was actually very easy to take the odometer apart. Just make a note of where things go so you can put it back together again!
 
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