Speedometer bouncing

If the nut is tight and the angle drive still moves, you need to remove it and wind the nut back a little on the angle as it is like a barrel nut and runs on threads both sides. It can be a bit oif an iterative process to find the right spot where it tightens all the way on the ZF case and the angle drive does not move.

If I recall correctly it is also a left had thread.

The angle drive is a gear so there isn't much that can casue jumping, verify it operates freely. If they bind they normally break at the drive pin. I'd put the jumping down to the cable sticking, did you grease it prior to install? You can attach a small drill to the drive end and run it to see if it causes the speedo jumping.

Good luck

I used to get speedo bouncing on an old european daily driver on very cold days. It was concluded to be the speedo cable (a very long narrow spring inside a sheath) that was binding slightly and would spring back when it freed itself causing the needle to bounce.

Julian's test is a good one. Lubricating the cable properly (if it's not a sealed cable) and avoiding any kinks in the cable path is the most likely cure.

Mark

I've read on other boards that it would work better to use extra fine graphite to lube the speedo cable. So for the heck of it, I did it to my "other" car, the speedo cable is not as long, but it really worked well. I used brake cleaner to get the grease off the inside and the metal spring. The motion of the speedo on my "other" car was smooth and gradual.
I would recommend to anyone else that wants lots of lubrication in all areas of the cable.

Mark

quote:

use extra fine graphite to lube the speedo cable.

Mark,

Can you share your technique used to get the entire cable coated with the graphite?

Larry

Okay,
1) I did not lube the new cable before installation.
2) So yesterday, I pulled the end off the speedometer, held it up-right (by un-snaking it from behind the pedals it is long enough to have plenty to work with , put powdered graphite in the end, and drove around while rotation/vibration/gravity allowed the graphite to be "ingested".
3) Re hooked it up and "played" with the cable routing/alignment until is was optimized...great (pretty stable and quite) but not perfect.

Larry,

The way I did it was to take the cable out of the sheath. I soaked the cable in brake cleaner in a clean pan. I then brushed it with a toothbrush sized brush to get all of the grease out of the cable. Then I sprayed brake cleaner in the cable sheath multiple times until the "grease" color did not come out anymore. Then I dried the cable sheath with low air pressure out of the compressor. After the cable and sheath were dry of brake cleaner and grease, I started reinstalling the cable in the sheath; and as I did that I continually dumped extra fine graphite in the area of the beginning of the sheath -- I tried to "drag" as much extra fine graphite as the cable would take. Do this very slow if you want to try it; and also make sure that you put paper or towels down that you want to throw away -- it makes a heck of a mess.

Again, I did this on my 1971 Hemi Cuda this past summer; and it really worked like a charm. The only caveat is that your sheath and cable needs to be in really good condition -- because if there is slop or is worn bad, nothing will get the slack out of it save a new cable anyway.

Mark

Thanks Mark,

Yup, I've used that graphite many times. It is THE lubricant for locks.

But it is so fine it firmly settles into every pore and fingerprint it finds. Gloves and towels are a must for a project like this.

Larry

Speedo cables run inside a steel housing with a poly liner between the two. If a speedo needle starts jumping, its almost always because the rotating inner cable has worn through the plastic liner and is catching on the worn liner edges. No known lube will permanently cure this problem. Normally the cable continues to catch until it finally breaks. You should replace the entire assembly since the liner cannot be removed and a new inner cable simply catches and breaks on the same worn area in old housings. Re-routing for shallower bends minimizes liner wear, and tight bends increases it. New assemblies are teflon lined which helps the wear problem a little.

Maybe I had excessive bends in mine...BUT it is less than a year old.

I agree with Jack. I pulled & lubed mine. It lasted about 10 months before breaking. I got the replacement from Wilkinson for just under fifty dollars. That was about 2 years ago. Jack made a great piont, no sharp bends. Maybe you last one was defective?

#4134 had chronic low speed speedo bounce. I pulled the inner cable and soaked it in a bowl of WD 40. I than used fine emery cloth to remove any rough edges. Re cleaned in WD 40. Lots of rags and allowed to air dry.
I re installed the cable with a NAPA product called Syl-Glyd. First coated the cable and applied more in the opening of the cable sheath as I re-inserted the inner cable. That was a year and half ago and no speedo bounce.