Speedometer cable service - how to

[84-C20]

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.

You must be registered for see images attach

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

You must be registered for see images attach

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?

 

[84-C20]

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.

 

[hack_man]

@84-C20 This is an old thread (and so is my '83 K10!) but you hit on my exact problems (chirping noise and bouncy speedo needle especially below 25 MPH).

Why did you say to grind the cable at both ends and not just one end?
Is graphite lube better or worse than the Sil-glyde?

For the first time today, I think it happened when I was backing up, the speedometer needle went WAY below 0 MPH but came back when I went forward. What would cause that?

 

[edgephoto]

I have in my tool box a speedo cable lube tool. Hooks to a drill and you spin it at the transmission end. It lubricates the cable and works pretty good. Back in the day this was something you did regularly so this tool paid for itself. Charge an hour to lube it and do it in a few minutes, profit!

I think mine is Blue Point but I am pretty sure it is made by Lisle. Not sure if you can buy them anymore.

Whatever lube you choose be sure to get something that does not get real stiff in cold weather.

 

[84-C20]

@84-C20 This is an old thread (and so is my '83 K10!) but you hit on my exact problems (chirping noise and bouncy speedo needle especially below 25 MPH).

Why did you say to grind the cable at both ends and not just one end?

Because on the speedometer end there is a thing on the cable that prevents it from being able to be pulled down, this is why the cable can only but pulled up and out from the speedometer end. We don't know for sure which end has stretched the most although it would be most likely to be the part after that stopped, so I always take just a little off each end and that has worked very well for me in a lot of applications.

Is graphite lube better or worse than the Sil-glyde?

Everyone has certain lubes that they have developed a likeness for so I'm not shooting down graphite. I have never used it for speedometer cable lube. My feeling has always been to go with Sil-glyde and from what I have seen using the method I described here will last a long, long time. Is this a graphite based grease you are talking about? Or a spray. I would discourage you from using a spray because it won't last. And I can't tell you how well a graphite grease would work because I've never tried it, but it's just a speedocable in the end it would probably work out ok.

For the first time today, I think it happened when I was backing up, the speedometer needle went WAY below 0 MPH but came back when I went forward. What would cause that?

You sure that was the first time? I mean speed can play a roll to the faster you go backward the further past zero it's going to go. There is no stopper for the needle so that can happen. I'd say it's normal.

 

[hack_man]

I pulled the cable and greased it with Sil-Glyde. The chirp chirp noise is all gone but unfortunately the needle bounce at low speed (<25 MPH) is still there. I was hoping the grease would fix the bounce too but no luck. It was some work to remove the cable, you have to remove the front of the dash and pull the speedometer itself. The cable is completely inaccessible from behind the dash. Guess the next time I have reason to change a bulb back there or have to dig into the dash I'll try shaving some off the cable. The Speedo end of the cable has a plastic rectangular cap built into it that fits inside the speedo unit.

The reversing needle when backing up may have always been there, funny I just never noticed after all these years. Maybe I noticed because I'm more aware since it started acting up.