Bouncing and Squealing Speedometer

Every once in a while, the speedometer on my '65 Skylark will start bouncing back and forth from 0 to 120mph, all the while making a loud squealing noise. After a few seconds of that, it returns to whatever speed I'm cruising at, goes quiet and holds steady.

Any ideas as to what's causing this?

 

take the cable loose at both ends , pull out the inner cable from the plastic sheath.If the cable isn't frayed , clean it and spray some graphite on it ,reinstall and it should work fine

 

Thanks.

The cable looked fine. Still gave it a graphite treatment anyway.

The speedometer's square hole was destroyed though. Looks as if it's nearly rounded out. I'm still trying to clean out it to be certain of what I'm seeing. When I started cleaning it out, it dumped a small pile of metal shavings out the needle side of it.

Just in case this one can't be saved, I started shopping around for '65 Skylark speedometer assemblies. Just the part that included the speedometer-cable-insert, the needle and odometer (which I can replace with mine). I couldn't find anything that didn't include the entire instrument cluster. Does anybody know of a good source?

 

As it turned, the cable was in good order and the problem was part of the speedometer assembly. Where the cable plugs in, there a shaft that passes through the cast body of it and drives everything else through a gear (to the odometer) and a magnetic coupling (to the speedometer).

The problem with this shaft is that it got gummed up with graphite and could not spin freely. At lower speeds, this wasn't a problem. At higher speeds, it would drag just enough to upset the connection between it and the speedometer cable.

As an experiment, I shot a bit of WD40 at that point and turned it until it spun freely (incredibly freely). Road test ran great. I didn't expect the WD40 to perform well for very long (I don't consider WD40 an all-prupose lubricant) and after many months, the problem started coming back.

Does anybody know what the right lubricant is for this spot? If it is graphite, then why does the graphite on mine get gummy and what can I use to break it down?

 

Hit it with a shot of silicone spray

 

It's already starting to misbehave again. I may have to admit defeat and retire this one.

Does anybody know a source for a good replacement speedometer that will drop into a '65 Skylark?

 

Isn't there anyone that could rebuild it?

 

Bob's Speedometer

http://www.bobsspeedometer.com/1/120/index.asp

 

I'm ready to replace this speedometer assembly now. Not restore it, but to actually replace it. What vendors do you recommend (for or against) who sell such an assembly?

 

I'm even open to buying a used one. Checking out ebay and Craigslist next week.

 

Stop wasting your time & eventually your hard earned $$$$. You MUST remember these units we are dealing with are 50+ yrs. old. Buying used you will eventually run into the same problems, if not now eventually. It may cost you a few $$$ more in the beginning, but in the long run will save you the time & aggravation of having to CONSTANTLY taking it apart AGAIN!!!
If I may make a suggestion. I have been using D & M Restoration for yrs. at my shop. NEVER any problems.
46 Grand Ave. Greenville, SC 800-722-0854

Just my humble opinion.


Tom T.