I have 1986 Z28, 305TPI. My speedometer is broken, all the needle now does is just spin in a complete circle. Before this, it partially worked and would wobble all over, and likely was about 10 MPH under actual speed when it would hold near steady. The speedometer I have goes up to 145. What could have been failing that has now caused complete malfunction? (The odometer continues to register mileage.)

I'm uploading two pics, the dash with the odometer/speedo assembly removed, and what the dash looks like where that assembly plugs in.

Any ideas greatly appreciated.

 

Wish I could help but can't. I will be watching this post to see if someone can. I love the 3rd gen cars. I've never had this problem, but some day I might.

Good Luck

 

Big problem is there are very few 3rd Gen owners on the site any more. I'm not sure we can survive much longer as an "LT1" site. I try to help where I can, but something like the speedo is not all that familiar to me.

 

This seems to be a stumper. Has anyone ever changed the speedometer to an aftermarket version? How is that done, how is the spindle removed from the cable? What work would a new speedo require? Further digging into or behind the dash looks more troublesome....Thanks for any suggestions or ideas.