Fix your Speedometer Cable

3A-C Power · Post by **3A-C Power** » Mon Sep 13, 2004 5:29 pm

I had to fix mine recently after it broke while off-roading and in doing so I discovered a common problem. The fitting that goes into the transmission and holds the cable tends to get loose and crack and corrode, causing a wobbly cable. This causes the needle to wobble also, especially at low speeds. There is a rubber hose covering this fitting, so you don't see it until you take it apart.

Once you get the cable off by unscrewing the nut at the transmission end (you don't have to take out that whole 90 degree bevel gear assembly) you can pull out the inner cable and then pull off the metal part and the rubber hose. The rubber hose is probably swollen and loose, being part of the looseness problem. The end of the metal part is probably somewhat cracked. This is actually crimped onto the cable during assembly but if it is loose, this crimp is no longer any good and the metal part will probably slide off easily.

I opened up the metal part where the cable sticks in by using a punch about the same diameter as the cable (a small socket would work good). Then to replace the old rubber hose I used a section of air line (nice and thick is better). My work throws out lots of stuff like this, but at a parts store there's probably a fuel line that would work. You want something that's as close to the size of the cable while still being able to slide over it and the metal fitting. You want a tight fit. To put it together, put the hose over the outer cable, then put the outer cable into the metal piece, get it in as far as you can, and then put the hose over the metal piece. Put a hose clamp over the metal part and right next to it.

This would be a good time to grease the cable so it doesn't give you any trouble. Unless you were really careful, the inner cable probably got dirt or grit on it, so it will have to be cleaned with some kind of solvent and a rag. I went the full 9 yards and took the whole cable off, degreased it and blew it off with compressed air, and used expensive synthetic grease from work. There's not a lot of load or heat here, so the kind of grease probably doesn't matter.

This can all be done without removing the outer part of the cable from the firewall or the speedometer. I would actually recommend not removing it because it's really hard to get the grommet that seals the cable back into the firewall correctly.

This job was 100% successful on the first attempt when I did it, and now the needle looks perfectly steady at any speed. I would recommend this to anyone.

takza · Post by **takza** » Mon Sep 13, 2004 5:38 pm

There is one caution with using any kind of grease on a speedo cable...if it's too heavy a grease, you might have problems in winter when it gets real cold...best to use an oil on the cable.

When it's cold the grease can cause the cable to have too much stiction vs it's housing and can even break the cable.

Grease is best in the gears at either end.

3A-C Power · Post by **3A-C Power** » Wed Sep 15, 2004 5:06 pm

My speedometer needle now shakes excessively at any speed, so I will have to find out what went wrong. I should be okay with the synthetic grease because it is good at keeping its properties over a wide temperature range.

takza · Post by **takza** » Wed Sep 15, 2004 5:26 pm

The first time I took one out I managed to kink the cable that is inside the housing....and had the same problem.

Also...I put a bunch of axle grease on it. I had to clean the grease off and use oil.

If you roll the cable on a flat surface you might be able to see the "bent" areas, if there are any and maybe carefully straighten them. I think those cables are a standard item that you can cut to length...they come with a staking tool to square the ends.

I think the needle jumps because the cable drags and then speeds up again... over and over.......or it could be in the head unit...which is what they call the mechanism in the speedo?

3A-C Power · Post by **3A-C Power** » Sat Sep 18, 2004 5:29 pm

The speedometer cable is now working fine once again, thanks to me doing nothing to it for about 3 days. I checked it this morning and the joint to the transmission feels a bit loose, like the air line isn't quite doing its job. I will probably make another metal adapter with a nice long sleeve to keep it tight, and make it thicker than the original so it will last.