Jumping Speedometer

[Cornpatch MO]

I did all that when I restored the car. The cable works flawlessly. I

I did all that when I restored the car. The cable works flawlessly. I am sure it is either the gear (though I would have expected the transmission shop to notice that) or the speedo. I will run it on jack stands and see how the cable spins the housing.[/QUO

 

[Cornpatch MO]

I did all that when I restored the car. The cable works flawlessly. I am sure it is either the gear (though I would have expected the transmission shop to notice that) or the speedo. I will run it on jack stands and see how the cable spins the housing.

Believe me and all the other guys that have said so--your speedometer head is bad. If you leave the speedo cable hooked up, you will screw something else up. See if you can turn the ferrel that the speedo cable fits into on the back of the speedo by hand . If it is hard to turn, and needle doesn't move, it is about to freeze up. ( if it hasn't already) I speak from experience , and now have to take my speedo out . Old speedo's had a lubricating wick, but my 64 does not. I do not know of any way to lube it..........................MO

 

[Bruzilla]

Sounds like your cable is fine. The problem is most likely the grease inside the speedo itself has dried out. I had the same problem with mine, and the only real fix is to remove it and send it off to be rebuilt.

An interim fix that worked well with mine is to disconnect the speedo cable from the back of the speedometer, stick the business end of a can of WD40 in through the hole, and give the unit a couple of good squirts. My needle still jumps around from time to time, but it's largely settled down since I did that.

 

[not so famous bob]

Sounds like your cable is fine. The problem is most likely the grease inside the speedo itself has dried out. I had the same problem with mine, and the only real fix is to remove it and send it off to be rebuilt.

An interim fix that worked well with mine is to disconnect the speedo cable from the back of the speedometer, stick the business end of a can of WD40 in through the hole, and give the unit a couple of good squirts. My needle still jumps around from time to time, but it's largely settled down since I did that.

I cleaned and lubed all of the above. used weedeater cable lube on the cable. mine jumps up and down about 5 mph ( 2-3 over and 2-3 under at speed. everything turns easy w/ no tite spots or frayed cables.

 

[themechanic]

Take the speedometer out and spray WD-40 in the cable inlet, soak, repeat a few times.

Buy a new cable.

Lube the cable.

Connect cable to speedometer (out of the car) and run with a drill to test. If it still bounces you need to send your speedometer in for repair.

 

[Bruzilla]

I cleaned and lubed all of the above. used weedeater cable lube on the cable. mine jumps up and down about 5 mph ( 2-3 over and 2-3 under at speed. everything turns easy w/ no tite spots or frayed cables.

The cable is not the problem. It's the speedo itself. Squirt some WD40 directly into the speedo through the back.

 

[mopar 3 B]

Am supprised no one has had a speedo apart. What do they do with it a rebuild?

 

[JimKueneman]

It is the speedometer... my victory drive was short lived, need to get the cluster repaired before I can drive it again... That thing is WAY easier to deal with with the dash out of the car.....

 

[not so famous bob]

Am supprised no one has had a speedo apart. What do they do with it a rebuild?

I had mine apart to reset it to 000000, nothing looked worn or broken at the time. Think I can live w/ the bouncing, compared to pulling that crap out again ! lol

 

[Malicious]

I originally had 4.56 rear gears and a random speedo gear pinion in the box. Swapped it over to what I thought was the correct one (but it still read out of spec) and had the speedo jumping all over the place as well.

I just recently swapped the rear gears over to 2.76, for better high way manors until I sort out some sort of overdrive solution, and left the 4.56 speedo pinion in there and my speedo is now solid as a rock. In correct, but solid. I've just checked the speed via GPS app on my phone and referenced it to what the speedo is reading. Its a good out come for me.

I guess this raises some questions though, what is actually causing the jumpyness if it was solved through changing the rear end ratio?

 

[Cornpatch MO]

I originally had 4.56 rear gears and a random speedo gear pinion in the box. Swapped it over to what I thought was the correct one (but it still read out of spec) and had the speedo jumping all over the place as well.

I just recently swapped the rear gears over to 2.76, for better high way manors until I sort out some sort of overdrive solution, and left the 4.56 speedo pinion in there and my speedo is now solid as a rock. In correct, but solid. I've just checked the speed via GPS app on my phone and referenced it to what the speedo is reading. Its a good out come for me.

I guess this raises some questions though, what is actually causing the jumpyness if it was solved through changing the rear end ratio?

Maybe your speedo drive was not clockde quite right. On mine, I had it engage the teeth but had to much clearance between the teeth= to much play. I never tried it that way, but I would think that could cause needle jumping...........................MO

 

[Qbrozen]

What have folks been seeing in terms of rebuild costs for speedos? I just got a quote from Southern Electronics (aka, southernelectronics.com, instrumentclusters.com, carradio.com) for $345 to just rebuild the speedo and nothing else. Seems excessive.

 

[JimKueneman]

What have folks been seeing in terms of rebuild costs for speedos? I just got a quote from Southern Electronics (aka, southernelectronics.com, instrumentclusters.com, carradio.com) for $345 to just rebuild the speedo and nothing else. Seems excessive.

Dicks in Phoenix said $185. Tucson shop said $200-$300 depending on parts

 

[Wietse]

I have the same issue with a jumping speedometer.
The tranny gear was in good condition and the cable is new, when inspecting the speedometer i found there is a sort of centrifugal clutch driving the needle.
On mine i found there is quite some axial play on the cable side of the "clutch" which is causing an intermittent contact with the needle side causing it to bounce as it gets some friction from time to time.
The mile counter runs properly, as seen in the back it is been driven by the gears without issues, just the needle is messed up.

I decided to completely replace the speedometer with a new one from Classic Industries as this little stuff is so fragile to repair myself and here in the Netherlands it will be hard to find a shop who rebuilds these.

 

[miller]

Old speedo's had a lubricating wick, but my 64 does not. I do not know of any way to lube it..

Is your speedo the stock 64 gauge? If so, yeah, might be going bad. But, for what it's worth...just finished working my 64 panel, and had seen words on pulling a small brass 'cup', or plug, that covers the wick.
Decided to go the course, cleaned that little cup, and was surprised by the cup having a small hole in it. Cool! Simply filled the cup with 3 in 1 oil, twice, letting the oil soak into the wick. Gauge turns real easy, now.

 

[themechanic]

I called a speedometer and gauge restoration shop and told them my speedo was accurate but jumping/bouncing a bit. They told me I needed my speedo rebuilt. However, since it was out of the car, I took the advice of a FBBO member and sprayed WD40 into the hole where the cable goes and let it soak. Then sprayed it again and tested it with a drill and old cable. It works like new now.

 

[JimKueneman]

I called a speedometer and gauge restoration shop and told them my speedo was accurate but jumping/bouncing a bit. They told me I needed my speedo rebuilt. However, since it was out of the car, I took the advice of a FBBO member and sprayed WD40 into the hole where the cable goes and let it soak. Then sprayed it again and tested it with a drill and old cable. It works like new now.

Wish that was all I need. Mine clearly has a bad plastic bushing.

 

[Qbrozen]

I have the same issue with a jumping speedometer.
The tranny gear was in good condition and the cable is new, when inspecting the speedometer i found there is a sort of centrifugal clutch driving the needle.
On mine i found there is quite some axial play on the cable side of the "clutch" which is causing an intermittent contact with the needle side causing it to bounce as it gets some friction from time to time.
The mile counter runs properly, as seen in the back it is been driven by the gears without issues, just the needle is messed up.

I decided to completely replace the speedometer with a new one from Classic Industries as this little stuff is so fragile to repair myself and here in the Netherlands it will be hard to find a shop who rebuilds these.

This is my problem, too. There is play in the "axle" and, when the speedometer is upright, the metal cup-like thing is sagging a bit and contact the magnets, which drag and release, causing the jumping. If I hold the speedometer upside down and spin the cable receiver, it runs smoothly. If I could figure out how to disassemble it, I'd grind down the magnets a hair

 

[JimKueneman]

This is my problem, too. There is play in the "axle" and, when the speedometer is upright, the metal cup-like thing is sagging a bit and contact the magnets, which drag and release, causing the jumping. If I hold the speedometer upside down and spin the cable receiver, it runs smoothly. If I could figure out how to disassemble it, I'd grind down the magnets a hair

I messed with it a bit too and decided it was way to delicate and I would do more harm than good