During the Moonshine Cruise during the gathering in Effingham, my speedometer started to freak out.  It had been doing some clicking during our Route 66 trip, then later some bouncing...  During the cruise, it hit 160+ mph then bounced back to normal.

 

Eventually on the drive home, it started to REALLY whine and cranked up to 160 mph consistently Click for Pic. 

 

Shortly after this picture was taken, the needle actually started to bend as if it wanted to go farther (almost like you see in a cartoon) and eventually snapped off!

 

I have replaced the speedo twice in the car.  First time, I bought one off e-bay, had it refurbished and installed it myself.  Within a year, the tripometer on that one was not working, so I had the original one refurbished and had that one installed.  So this is the original that is now out of service.

 

My thought now is to just buy a new one from MAM (glad to give them my business).  Mitch also mentioned a cable lubricator from them (609-467).  He thought that was the issue with why it was squealing in the first place.  I think that route may be cheaper than trying to find another on e-bay and refurbishing (I sold the spare I had on e-bay after re-installing the original).  I also need to understand how set the odometer to the correct mileage once I get the new one.  I figured I'd get a new cable and housing at the same time too.

 

Has anyone ever used these (cable lubricators)?  Is it a permanent install or just an occasional maintenance item.  I list that I also have Tach troubles.  Those issues have also related to the cable (being a 74, my tach runs directly off of a cable from the distributor). 

 

For those of you who have worked on these gauges before, you know what a pain it is.  I want to be DONE with this issue and get it fixed and be able to keep it fixed once and for all!

 

Advice and thoughts requested.

The problem with your speedo is not gonna be the cable...it's the speedo head(gauge) itself. Not saying that the cable might not be in need of some love, but the needle pegging like that is a problem in the head. No way around it...yer gonna have to pull it and replace/repair.
The cable spins a "can" in the head. The "can" has a small magnet in one spot. The needle is attached to a clock-spring(coiled spring) with a ferrous tip on one end. The can/magnet fits over the spring. As the can with the magnet spins, the magnetic attraction of the metal on the spring causes the needle to move, giving you a gauge reading. Sounds like something has gotten between the can and the spring assy, causing it to be "direct drive"....not gud...

This might help

Thanks guys.  Joel, your explanation makes more sense, especially since I forgot to mention one little detail - the odometer still appears to be working (and appeared to work correctly during the 160+ time.

Not to hijack the thread, but while on this subject, I too have a speedo issue, mine works, but the speed reading is off about 10 MPH. My trip odomomter doesnt work my regular odometer does work,  but it too is out of calibration judging by me tracking mile markers on the highway. Is one related to the other (probably right?) but which one? So I was planning to send out the entire speedo to be rebuilt. Do you think that will solve these issues too....

A couple of simple things to look at. on my 77 to change the trip meter you pull down and turn to reset to 000 if you do not push it back up it does not work, as to accuracy mine is about 5 mph off but I beleive it is do to the tire size on the rear wheels.

I think you may have the wrong spedo gear in the cable. You can easily get under the car ....ok well nobody can easily get under the car.....  unscrew the cable going into the tranny and look at the color of that gear, different colors for different ratios. Someone,  Joel for sure should know what color it should be. Then go out and check it like we did running down the road with someone. You seemed to be off exactly 10 mph......but at least it was under and not over. "Well you see officer my spedo said I was doing 80 but actually I was only doing 70, you see my gear is the wrong color and I need a pink one.....it's so hard to find parts for theses cars you understand right......Yes sir....well no sir.....ok sir , I understand sir, drivers license, registration, and insurance card....right away sir"

ebo2011-05-27 10:09:35

   Hijack.............

Sorry there is no "PINK" your safe

ebo

http://www.transmissioncenter.net/speedometer_calibration_______va.htm?gclid=CMHMwYTOiKkCFQEQbAod6GxFoQ

ebo2011-05-27 10:18:39

Whew!!!!!!