The needle on my speedo (1968 GTX non-rallye) does not return to zero. The coil spring at the base of the needle can be turned to apply spring pressure for returning the needle but I can't see how the spring is supposed to be fixed in location. I can turn the spring so that it works but when I bench test with drill and cable it moves the spring. I never drove the car prior to restoration so I don't know if it was working then. I have pictures but I don't have a website and I didn't realize that photobucket requires membership now. I guess I'm just a hot mess here!
Any help appreciated
Chuck

Post your pictures here. Use the File Manager at the bottom of the reply screen.

Thanks for the tip, attached a couple pics, will see if it worked.

bushing broken

could be fixable thought. BTDT

http://wichargerguy.proboards.com/thread/19119/patiente-pays-brock-thing-help?page=2

ooops, it seems some pics are missed on the threar I posted. Just the broken piece is the one shown.

anyway, it can be fixable with some epoxy and patiente... If I find the pics around, will post.

The bushing not only keeps the needle shaft in place but also keeps a light pressure over the tension spring lever ( which is a spring too ), and melted on back to keep in place that.

I used a fork to reinsert the bushing and apply epoxy glue over the bushing and speedo assembly ( taking care not apply over the needle shaft ), keeping the fork in place untill epoxy dries out.

then used a drill in reverse speed to "recalibrate" the speedo. Coil needs to be got back to the same position adding the spring tension and keeping the speedo calibration.

"anyway, it can be fixable with some epoxy and patiente... If I find the pics around, will post."

"The bushing not only keeps the needle shaft in place but also keeps a light pressure over the tension spring lever ( which is a spring too ), and melted on back to keep in place that."

Same thing happened about twenty years ago to my speedometer on my 68 Coronet. It's that bushing in back. If it comes out or gets missaligned
, will cause the needle to stick in one place. As mentioned previously, JB weld and reposition the bushing was the fix for me too.
Easy fix. Just got to get the instrument cluster out to do it.

Had that problem on my '69 RR, needle would stick at 55mph as it came back down from whatever speed I reached. A couple of taps on the front of the speedo with my finger would free up the needle and then all was normal again until the next deceleration from more than 55 mph. I learned to live with it.

Here the broken section on back of bushing and the fix. I used a fork and some rubber bands to keep the fork in place againts the speedo assembly while it keeped the bushing in place. Then added epoxy just on back.

Becarefull with the shaft to not fill it with epoxy. The bushing needs to keep some pressure over the spring adjuster lever.

Thanks for the pictures NachoRT74, I have a better understanding now. The way I'm interpreting, I can calibrate the speedo after the bushing has been epoxied in place by rotating the coil spring under the needle, is that right?

Yeap...

1000 rpms equals to 60 mph

I used a 550 rpms drill with reverse feature ( because is the one I had in hands ) and a piece of an old speedo wire to calibrate the tension spring... 550 is around 33 mph.

The glue must be just on back. Nothing must get the front, because will stuck the lever.

Once you get the speedo in hands you'll figure it out. The most tricky deal is try to hold the bushing in place while the glue dries. As mentioned I used a fork and some rubber bands able to press againts the bushing in place.

Old speedo wire section ( one of the ends... both work the same ) between drill and speedo.

Then run the drill for 5 minutes ( I couldn’t test for more time because my drill began to heat ) untill get the speedo set and matching with odometer.

At correct speed 5 minutes the odometer should get 2.75 miles with a 550 rpm speedo at 33 mph aprox. Make your maths with your drill speed.

If you drill doesn’t heat, could run the drill for more time. I made this several times untill match the best I could.

( this is a Kilometers speedo, that’s why you notice the diff scale ).

if you find two drills with diff speeds, could make the test at diff speeds. I just made this because is the only one I had and nobody around had one with a known speed spec and reverse speed feature.

Thanks for your help NachoRT74! After getting a close look at that old dry plastic bushing it seems to me like this would be a typical problem for ~50 YO cars. The repair was a success and I was able to calibrate the speedo (850 rpm / 51 mph) with a nice firm pressure holding the coil spring in the set position (after the epoxy cured). As you said the trickiest part is holding the bushing in place. I couldn't quite visualize how to use a fork so I made a simple sheet metal clip to hold it while I applied the epoxy.

Great!!!