Speedometer broke. For the second time.

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prorac1

prorac1

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1965 Plymouth valiant gauge cluster. Cheap aftermarket replacement cable.

Speedometer works fine for a couple of thousand miles. Then it starts bouncing all over the place and stops wherever it wants. Usually around 30 mph. You reach up under the dash, unscrew the cable from the speedometer and it falls back down to zero. You screw it back in and take it for a drive and it works for a little bit and then does it all over again.

I talked to a couple of speedometer shops on the phone. The price they were quoting to fix the speedometer was astronomical. Upwards of $450.

But here’s where the confusion starts. The first shop told me it was because my cheap Chinese cable was too long and putting pressure on the back of the speedometer. The second shop, which is also been in business for 60 years, told me that this is not possible. And then I just happen to have two shitty speedometers that broke just after installation.

Can anybody shed some light on the subject? I know I need to find another speedometer head, or get one of these repaired. But cut the cable because in this problem? What is the solution.

Thank you in advance. Eric and Jason.
 
run the shortest cable possible and the least mount of bends....obviously no hard bends.....lube cable
 
bbrroowwnn said:
run the shortest cable possible and the least mount of bends....obviously no hard bends.....lube cable
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The cable is a little on the long side. It’s been lubed multiple times. But I wouldn’t think that would stop the speedometer in its tracks. Unless the speedometer cable inside is too long and binding into the back of the speedometer like the one guy said. Thanks. Eric
 
Any chance the input shaft of the speedometer/s has too much slop and if the cable puts a side load on it, it might cause a bind?
 
Dana67Dart said:
Any chance the input shaft of the speedometer/s has too much slop and if the cable puts a side load on it, it might cause a bind?
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That I’m not sure of. I will have to check it. It’s a definite possibility. From what I remembered it was pretty tight.

jeffnmo said:
You said you lubed it, with what. Try Graphite, it always worked for me.

Jeff
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Yep. Dry graphite lube. I have a bottle of it around for things such as this

4spdragtop said:
In 67 there is a small brass spacer in between cable and the speedometer. Ours was missing and caused same issue. Not sure if this applies for yours?
Try these guys?
ATP Automotive | Automatic Transmission Parts
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That’s a very very good point. I will have to check. I thought I remembered the cable having a stop on it at the transmission end. But this very well could be the issue. If that’s the case we will just buy a new cable and another used speedometer head and try again. Because the money they want to repair a speedometer head, not restore the entire gauge, but just to repair the head is ridiculous.
 
Not sure where you bought it from? I would call ATP directly. We also received the wrong one....ordered thru Rock Auto. Was an ATP product.
 
Since you have 2 "broken" spedos open one up and see if you can find an issue. It might all be the cable is spacer
 
4spdragtop said:
Not sure where you bought it from? I would call ATP directly. We also received the wrong one....ordered thru Rock Auto. Was an ATP product.
Click to expand...

We bought ours through rock auto also. Came in an ATP box with the proper part number on it. Seems to fit well. I’m going to have Jason pull the cable off the speedo head and see if there’s a collar on it.

The collar should be on the speedometer end, correct?


Dana67Dart said:
Since you have 2 "broken" spedos open one up and see if you can find an issue. It might all be the cable is spacer
Click to expand...

On the first speedometer that went the Gyro internally kind of went kitty Wompus. We haven’t pulled this one apart yet to check it. We’re kind of planning on doing it this winter. For the places he drives, mostly rural, he will be OK without a speedometer for a month or two
 
Yes the collar is between the end of cable and speedo. Lol being the same circumstances as us I'm curious the part #?
prorac1 said:
We bought ours through rock auto also. Came in an ATP box with the proper part number on it. Seems to fit well. I’m going to have Jason pull the cable off the speedo head and see if there’s a collar on it.

The collar should be on the speedometer end, correct?




On the first speedometer that went the Gyro internally kind of went kitty Wompus. We haven’t pulled this one apart yet to check it. We’re kind of planning on doing it this winter. For the places he drives, mostly rural, he will be OK without a speedometer for a month or two
Click to expand...
 
Yep Y804 was listed on RA as well as ATP website for our 67. Wrong!
Lemme see what info I can find.
Fyi I called ATP and informed them about the issue 5 years ago. Obviously didnt do squat about it.
prorac1 said:
Y804 is our part number
Click to expand...
 
4spdragtop said:
Another link to a thread we started.
Speedo cable question
Click to expand...

So from what I’m reading here, our speedometer could be just fine. It’s just the speedometer cable binding in the end of the speedometer.

We just found the factory speedometer cable in good condition. We’re going to try installing that and see what happens.
 
Put the trans end of cable in a drill and with speedo end hooked up. Spin drill slowly and watch for smoooooooth speedo operation (punch line there somewhere lol)
Ben, @RedFish is very helpful and knowledgable with this stuff(and more)
 
Directional forces from the cable is what wears speedometers. Early models have simple collector nut providing very little alignment support. Later models have improved plastic sleeve like connector about a inch long to better align the cable and sheathe but... everything wears out eventually no matter how well it is designed.
Tiny bronze bushings and very little clearance between the speedometers rotating parts. Wear causes one to contact another. I have had pictures to share in the past that show scared on the outside of the drum shaped part, and closeup pics of the egg shaped bushing bores that caused it too.
All we can do is clean the crud from square input port so there isn't inward pressure, and align the cable and sheathe as centered as possible.
Since your collector nut and flange beneath is the only alignment support, to snug that nut is better than leaving it loose.
The cost to rebuild is relative to the availability and cost of replacement parts (those tiny naval bronze bushings, etc..). Their inventories of good used parts are surely depleted today.
 
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