Speedometer bounces all over the place

[Dakota Smith]

My 76 Plymouth Duster has a 340 and a different transmission in it than stock. It is a four speed transmission, but I’ve read on here that you can usually fix the speedometer problem by changing the speedometer cable, but would I need a different cable than what my car would need stock? If so, how would I figure out what cable I need?

 

[RustyRatRod]

Remove the cable from the speedometer. Remove the inner cable from the housing. It slides right out. Clean it GOOD with brake cleaner and let dry completely. Then liberally coat it with graphite and reinstall.

 

[pishta]

It may have a wire bur on it. Clean it like Rusty says, but watch out when you slide your hand over it so as not to catch a wire sticker. The graphite powder works great, stay away from WD40 as its not really a lube and also heavy greases.

 

[diymirage]

Quit doing burnouts

 

[jonn6464]

My 76 Plymouth Duster has a 340 and a different transmission in it than stock. It is a four speed transmission, but I’ve read on here that you can usually fix the speedometer problem by changing the speedometer cable, but would I need a different cable than what my car would need stock? If so, how would I figure out what cable I need?

I once had a speedo cable that was resting on the flange for the collection area of the headers. It had melted the outer protective layer of the cable and made the speedo jump around. I zip tied it up away from the heat of the header pipes and it was solved. Just something easy for you to look for.

 

[Dartswinger70]

You dont need a speedometer......

 

[Dakota Smith]

You dont need a speedometer......

It makes an annoying clicking noise when its bouncing around or I would not worry about it right now.

 

[Dakota Smith]

Remove the cable from the speedometer. Remove the inner cable from the housing. It slides right out. Clean it GOOD with brake cleaner and let dry completely. Then liberally coat it with graphite and reinstall.

Can you give me a link to what you mean by liberally coating it with graphite? I have never used that before. Thanks!

 

[RustyRatRod]

Can you give me a link to what you mean by liberally coating it with graphite? I have never used that before. Thanks!

That means use a lot.

 

[Dakota Smith]

That means use a lot.

I meant idk what graphite lubricant you’re talking about.

 

[stumblinhorse]

something like this:
https://www.amazon.com/dp/B007I9XUD0/?tag=fabo03-20
roll up your cable like a snake on a piece of plastic and spray it!

 

[RustyRatRod]

I don't use any type of spray. Get graphite powder. Any parts store has it.

 

[yellow rose]

That means use a lot.

LOL.

 

[famous bob]

LOL.

I cleaned and lubed mine w/ weedeater cable graffite grease. It and everything else seems to be in good shape, and it bounces about 5-6 mph. I couldn`t find any burrs on anything !?????????????

 

[stumblinhorse]

I don't use any type of spray. Get graphite powder. Any parts store has it.

I seemed to remember it stained the crap out of my hands. So I was thinking spray for next time!

I cleaned and lubed mine w/ weedeater cable graffite grease. It and everything else seems to be in good shape, and it bounces about 5-6 mph. I couldn`t find any burrs on anything !?????????????

Mine bounces at low speeds and I couldn't find any burrs either. But I sure could feel it catch when I spin it by hand.

 

[nm9stheham]

I cleaned and lubed mine w/ weedeater cable graffite grease. It and everything else seems to be in good shape, and it bounces about 5-6 mph. I couldn`t find any burrs on anything !?????????????

3 things:
- Sometimes the insertion of the cable core (or connection the whole cable assembly at the trannie end) does not properly engage the square end of the core into square hole in the speedo or trannie gear. The core will then erraticcally 'catch' and 'not catch'. I've had to turn the core manually at the trannie until the core is lined up so it will go right into the square hole in the trannie gear to make them mesh. I've also had to do the same thing at the speedo end.
- If the cable's outer jacket is stretched, then the core end can partially slip out of the mating square hole at one end of the system and make erratic connection.
- If the delicate springs inside the speedo break, it will jump around. You have to replace the speedo/dash cluster itself.

 

[famous bob]

3 things:
- Sometimes the insertion of the cable core (or connection the whole cable assembly at the trannie end) does not properly engage the square end of the core into square hole in the speedo or trannie gear. The core will then erraticcally 'catch' and 'not catch'. I've had to turn the core manually at the trannie until the core is lined up so it will go right into the square hole in the trannie gear to make them mesh. I've also had to do the same thing at the speedo end.
- If the cable's outer jacket is stretched, then the core end can partially slip out of the mating square hole at one end of the system and make erratic connection.
- If the delicate springs inside the speedo break, it will jump around. You have to replace the speedo/dash cluster itself.

probably the last one >

 

[604B1duster]

I remember a special grease gun adapter that you would hook to the cable after disconnecting it from the trans. It forced white lithium through the cable

 

[604B1duster]

 

[Yote]

Don't know if it means anything but I lubed mine VERY WELL with white lithium grease. It still bounces up to 60 mph and quits thereafter. Am thinking I will clean it and try graphite instead.
Yote

 

[famous bob]

Don't know if it means anything but I lubed mine VERY WELL with white lithium grease. It still bounces up to 60 mph and quits thereafter. Am thinking I will clean it and try graphite instead.
Yote

 

[nm9stheham]

I actually use Isky cam lube with a lot of moly in it for my speedo cable cores. The lithium tends to get hard when it is reeeealy cold.

Don't know if it means anything but I lubed mine VERY WELL with white lithium grease. It still bounces up to 60 mph and quits thereafter. Am thinking I will clean it and try graphite instead. Yote

Worth a shot. Check the cable core for any kinks/ burrs. If it is at all questionable, making and putting in a new core is not much work at all; there are kits around. I recall the same issue many years ago and I had to replace the speedo cable core IIRC. It was like it had a bend in it somewhere and would hang up at lower speeds, but which was not obvious to my eye.

 

[Krooser]

There are still a few "speedo" shops around that have skilled old people that can repair that speedometer. Back in the day they were plentiful... Just like "top shops"...

Powedered graphite is what you need...somewhere I have a an ancient container of Mopar speedo graphite with a little rubber bulb that squirts the powder into the speedo housing....

 

[Cuda Al]

these cars are 40+ years old the lube in the speedometer is old and the speedometer may need to be serviced. I replaced a cable once and still had the problem, took the speedo out and had it cleaned and lubed then all was well.


Alan

 

[1994redram]

I have bought a good used cable and two new cables. They all 3 have different issues. One of them makes the speedo ring like a bell. One makes it bounce at low speed ~35 and under and the other just bounces whenever it feels inclined to do so. I got annoyed one day and disconnected it under the dash and haven't cared much. I've used powdered graphite, cable lube, 3in1 oil, wd-40, and maybe more that I have forgotten. I'll get around to fixing it someday.