Speedometer cable service - how to

[SirRobyn0]

Sometimes folks have trouble / questions about how to diagnose speedometer issues. One of the most common issues is noise and speedometer needle bouncing. Although it is possible for the speedometer head to cause these issues it is much more common for it to be in the cable. 40 years later there probably isn't any lube left on the cable, and they stretch. Because the cable is strand wire twisted together the cable actually gets longer overtime which can put pressure on the back of the speedometer which can cause issues. Lack of lube can cause issues as well.

Step one disconnect the cable from the back of the speedometer, you can reach up there without removing anything. There is a tab you push towards the speedometer and the cable will pull off. Once the cable is off you can bring the end out from under the dash. Now all you want to do is remove the cable from the sheath. Needle nose pliers and the cable will pull right out of the sheath.

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Below: my cable, you can see the twist to the cable and that there is no lube. It was totally dry to the touch.

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So if your cable has a bunch of nasty old lube on it you'll want to clean it up. Diesel fuel, solvent, or brake clean doesn't matter, get it clean and dry. If you have gauge bounce your going to want to very carefully grind a 1 or 2 /32nds of an inch off each end of the cable. Use caution, you can always pull the cable a second time and grind a little more off, but you can't put it back on. Then lube the cable with grease. I like to use Sil-glyde, because it's a high quality silicone based grease that'll last for years and years, but honestly any grease will work. Get that cable covered in the grease, then start feeding it back in the sheath get a big glob of grease in your left hand, put it up at the sheath and feed the cable in with your right hand dragging the cable though that grease so a ton of it goes into the sheath with the cable. Once it's all in the sheath turn the cable until you feel it engage into the transmission end. Then feed it back up and clip it to the speedometer.

Enjoy many years of trouble free speedometer operation.

 

[77 K20]

My speedometer has been bouncing for years....

I'm sure a dumb question- but you can't take the cable out from the transfer case end?

 

[SirRobyn0]

My speedometer has been bouncing for years....

I'm sure a dumb question- but you can't take the cable out from the transfer case end?

Not a dumb question, but the answer is no. In my first picture the kind of blurry one but my needle nose plyers you can see the little orange ball that prevents the cable from being removed in that direction. So it only comes out from the head end, but I'm telling you I had mine out and back in, in about 15 minutes.

As a side note my gear selector indicator died earlier in the week, so time to order one of those a couple gauges that aren't working quite right and a circuit board, so for me if I need to take a little more off my cable I'll do it when I take the cluster out in a few weeks. I'll probably start another thread on that one of these days.