Sticking Speedometer

[Kodachrome Wolf]

Hey y'all,

I've encountered a bit of an odd issue on my '87 that started a little while after changing my speedometer cable. First the issue was a clicking/whirring noise from the speedometer head. Now I've encountered my speedometer either reporting speed slowly, or the needle sticking at the last reported highest speed, then erratically dropping down to 15-25 MPH when stopped.

This started really occurring on my trip to NC, and I chalked up the slowness to the low temperatures in the morning, however I've noted the speedometer tends to hang up even when warm for 5-15 miles. Eventually it'll stop hanging up and report speeds normally throughout the entire speed range at the time. The odometer appears to be reporting normally the entire time.

I feel the speedometer cable replacement might be a red herring in this instance and perhaps the speedometer head itself is sticking a bit, especially considering the needle will hang up at an incorrect speed for a while.

Is there an appropriate lubricant I should apply to the speedometer head to see if that rectifies the issue? I just want to take care with this particular unit since it's such an oddball and I certainly do not want to damage it.

[Tiggie]

I'd want to take good care of that speedometer as well. I'd try a lightweight oil like 3n1 on the speedometer. Be sure the cable isn't a hair long and/or putting pressure on the speedometer.

[WagonMan]

I have always used Dexron tranny fluid to lubricate my cables. WagonMan

[sly]

I used red and tacky on the cable in the 88. The speedo head I also used red and tacky but that doesn't like the cold but after a shot of PB blaster, it worked great. YMMV.

[friskyfrankie]

I've used ATP AT-204 Speedometer Lubricant. It's like $4-$5 a local store or can always be ordered online. Any kind of graphite usually works but as always is really messy!

[gadget73]

Not the red 3 in 1, that stuff is glue disguised as oil. The blue electric motor oil is fine, or any light, high grade oil. If you know someone who repairs clocks, that would be ideal.

on the cable, ATF is just fine. Probably OK in the speedo itself, the key is you want something that won't get gummy and you want an extremely small amount of it on the pivots only.

[Kodachrome Wolf]

I'd want to take good care of that speedometer as well. I'd try a lightweight oil like 3n1 on the speedometer. Be sure the cable isn't a hair long and/or putting pressure on the speedometer.

Wanted to follow this up since I used the wagon over Thanksgiving and got the issue resolved before I left. The issue was actually the speedometer cable. I had replaced it maybe about a month ago with a Pioneer unit since the original had a chafe and occasional scratchiness sound to it. I had found at the time it would not properly insert into the VSS and I had to lightly file the end so it would slide up into the VSS.

Apparently it was too long and at some point during my trip to NC prior, it shifted and jammed the cable up into the speedometer head which caused it to stick. I checked this symptom by spinning the cable by hand while forcing the cable forward slightly and could reproduce the sticking needle. Pulling the cable out released the head and the needle returned back to 0. I had to file the end down a fair bit before I could get a clean insertion into the VSS without being able to reproduce a binding condition. I had no issue over the course of my Thanksgiving trip, so I think it's resolved for now.

I'll likely see to looking around for a NOS unit, simply because so far I'm 0 for 2 on Pioneer's fit and finish of their products. Their accelerator cable lacked the correct mounting tabs at the intake and now the issue with their cable lengths and ends. Shame really, because the rest of the cable and connections worked as intended.

[87gtVIC]

Thanks for the follow up.

[Mainemantom]

Maybe you can find one or two original cables in good shape at a wrecking yard ? Aftermarket ones that I have used are flawed.