speedometer!!!! Help!!!

If the mile counter works your cable is ok. I would have to say that another speedo is in order.

if you need another speedo, i'm assuming for a GT, i have one that seems to work. never hooked it up, but the needle bounces freely, and if you put the eraser end of a pencil in it, and spin the pencil fast the needle jumps. let me know if you want it, 10 bucks its yours. on the front it says w=897 reads 61,560

If it helps any, I have the same exact problem. Never took any time to try and fix it though, keep us posted if you are able to fix it without a new speedo (unlikely though)

The opel speedo's are driven by a magnet and they have a clock spring that it acts against to make the needle go back and forth. The magnet is permanent on the drive shaft with little failure capability. But the clock spring could easily be broken in your speedo. These springs were adjusted for calibration so replacing them would be tough. They are interesting to take apart tho . One note on replacement, just keep your w= the same, it is the calibration.

I have a similar problem. When I got my GT the speedo was DOA. I replaced the speedo cable and found that the flex drive inside the 90 Degree drive off of the transmission was broken as well. I replaced the flex cable inside the 90 degree drive with a solid piece of rod and that got everything working, but my speedo jumps violently. The odometer works fine but the speedo is unusable. I can't decide if the problem is in the 90 degree drive or the speedo, what do you guys think?

Not long after I bought my GT a year ago, it did the same thing. Over the winter I took it out and took it apart. The spring that was mentioned before was OK but the needle was hanging up just enough that neither the magnet or the spring could move it. If I remember right the needle goes through a plastic bushing and then seats a sharp tip in another bushing. It finally freed up by just playing with it and readjusting. So far it is still working.
The biggest pain for me was taking the the chrome ring off and replacing with out cracking the glass.

Wayne

There really isn't an adjustment for that needle but there is one for the main shaft. I can see the nylon getting dry or something after time. It would also explain the stuck at 30 mph part.

Washout
I had the same problem with one of mine. I found out that they are fairly picky about length. as far as that 90 degree drive shaft. If it's too long it binds and causes problems. The stock one is 1.560 long and .1 square. it is made out of the flex cable like a speedo cable. I have one left.

Since I repaired it with the solid shaft I found some old Speedo cable. I'll try making a new drive with that and use your measurement. Thanks