Speedometer does not work

[buff_dog70]

I have a 82 diesel jimmy with a broken speedo.
2 piece cable, both cables turn. (Checked this with the vehicle raise, gear engaged drive, motor running)
It used to never move but I disassembled and I reassemble the speedo guage in the dash. Just disconnected check to make sure the cable turned on both ends reconnected.
Now it reads 0-30 mph (bumps up and down).

My service manual says bad speedometer head, is that the funny magnetic thing on the back side of the guage? or is it the screw in connection on where the cable comes in.

Any help would be great.

 

[4X4HIGH]

Bouncy needle is usually the speedo head itself. I have seen a bad cable do this also though. Try using cable ease to lube the cable.

 

[dyeager535]

Not really worth it to spend much time working on the speedometer assembly itself, dime a dozen, you can essentally use anything 1981-1987(9)

My experience with the bouncy needle was always the speedometer itself, but a cable that is binding can do it as mentioned.

 

[imiceman44]

Bouncy needle is usually the speedo head itself. I have seen a bad cable do this also though. Try using cable ease to lube the cable.

So far every bouncy speedo I had was the cable binding, they do that quite often, and since it's easy to fix, I would try that first and if it still bounces then change the speedo.

 

[buff_dog70]

How do you fix a cable?

Do you replace the inside or the whole assembly. If you lubricate what do you use?

 

[dyeager535]

They make stuff called cabl-eeze(sp?) for cables.

You'll see graphite mentioned quite a bit, but grapite is abrasive. I doubt you'd hurt anything with a very light coating of grease.

If the speedometer goes no higher than 30, and you are going 60, I'll bet money it has nothing to do with the cable. Even if the cable was binding it HAS to turn the speed of the speedometer output gear, at least at some point as it winds up and unwraps.

BTDT, started out with a bouncy speedo, then it would max out at 45MPH. It was the speedometer.