Speedometer jumping

[gazzol]

Hi guys as the title says my Speedo needle jumps around. I had a quick read on the internet and the concenus seemed to be that I needed to grease my cable. At this point I should say that the cable is not the original and I thought I'd got it from walloth nesch 3 years ago however a quick check of my order history says not, nevertheless I fitted a new one 3 years ago. So......I disconnected the cable at the gearbox and tried to pull the inner through but couldn't so I disconnected the cable from the Speedo and tried to pull it through but still no joy. At this point I thought that as I couldn't remove the inner to apply grease I'd apply some oil into the end of the cable and let it run down. I did this several times with a medium weight oil and then reassembled everything............. disaster, worse than before.
Has anyone had similar issues and apart from the obvious which is to replace it what can be done to fix it? I've had a quick look and they appear to be NLA in right hand drive.

 

[Beaudave]

Hi Preston, your thread is almost 3 years old, and you don't seem to have had any reply. I had a similar problem. I sent it here in France to the specialist Renotech, who fixed it. He told me on the phone that many times the problem comes from the cables, which square ends are too long, which apply some pressure inside the speedo, thus resulting in shaking and a trembling needle.
If that may help...

 

[ScottAndrews]

Most speedos, and I suspect this one is no different, use a magnet that is driven by the cable. The cable spins the magnet, and the magnet drags a metallic cup along with it (sort of like a magnetic brake on an exercise bike, but in reverse). The needle and the cup are also attached to a clock spring which causes the needle to return to zero when the magnet is not spinning. If the bearing of the needle is dirty or otherwise sticky, then the needle may be non-responsive, or it may jump. This can be caused by dirt and corrosion in the bearing, but it can also be caused, as @Beaudave notes, by pressure on the needle from the cable. Since the cable is spinning quickly, if it catches the needle in any way, it will cause the needle to jump.

I would think that one solution would be to simply add an o-ring to the inside of the cable end, so that the cable does not go as far into the speedo. The more extreme solution would be to trim the end of the cable, but that may be difficult, and it may introduce metal particles that could make the situation worse.

 

[nashvillecat]

First post suggests that problem worsened with the addition of grease. This suggests that problem might lessen with use of lighter weight lubricant. Of course, any cable kinks can impede free cable movement, and in some instances, this cannot be undone by new or more lubricant. Hence, the availability of universal cable replacements.

In days of yore, some mechanics carefully dripped automatic trans fluid into speedo end of cable and allowed gravity to do the rest. (Expect some clean up.) There are a number of products advertised for this specific purpose. As always, “your mileage may vary.”

 

[mulberryworks]

First post suggests that problem worsened with the addition of grease. This suggests that problem might lessen with use of lighter weight lubricant. Of course, any cable kinks can impede free cable movement, and in some instances, this cannot be undone by new or more lubricant.

The OP stated he introduced oil rather than grease into the cable end. If the grease had become hard and stiff, this could have resulted in a more fluid mix more like the original lubricant. If the proportion of oil to remaining grease was too high, the result would be mostly oil which may not have the ability to keep the spinning shaft from binding on the cable housing. Flushing the cable with the proper lubricant with some pressure would be the best way to ensure that it was properly lubricated. Hence the photo of the adapter in the red packaging in the above post. I've seen hand brake cables on vintage cars with grease nipples for just such a purpose.
I'd think lithium grease is probably a good lubricant for this purpose, but without the proper adapter to help get it down the length of the cable, it would be a difficult operation.

 

[adawil2002]

WD has a graphite spray I use for speedo cables. could be the square drive has compromised the interior metal sheathing & may be easier to replace it or have a shop deal with the replacement.

 

[Willem Tell]

Most likely the cable is not your problem. Watch this video:

and look at this photo.
It's a booger getting up behind the dash to see if this bushing on the speedo is pushed out. Perhaps you can use your phone camera to snap a photo. If the bushing has a gap like this, push it in by hand, and your jittery speedo will likely work fine. If you need to get the speedo out, that's a whole process in itself. Good luck!