I was driving my 85 SE today and noticed when I turned car off, speedo still read 30mph. I started it up and began driving and it did not move until, I can only assume, the car was doing over 30mph. It works fine otherwise but will not drop below 30mph while stopped or turned off. Any ideas?

 

Fixed it!

Maybe an FB veteran will figure this one out. Anyone want to guess?

 

Smacked the dash?

 

This might have temporarily fixed it but it surely would have gotten stuck again.

 

You can rule out the speedometer cable - the problem is in the speedometer itself.

A mechanical speedometer has a return spring that causes the needle to return to zero. When those fail the needle will have a tendency to bounce off the peg, flop all over the place and are usually not even close to accurate anymore.

So, I think something is interfering with the needle and I would surprised if the problem is in the internal workings of the gauge. I think it is possible that the speedometer needle is touching the gauge face. That would prevent it from returning to zero. If remember correctly the gauge face is a piece of plastic that is laid over a clear piece of plastic and it may have delaminated in that area.

Take some pictures if you can.

 

Close enough! Actually, what happened was, one of the two little screws in the middle of the speedometer had backed out, thus interfering with the needle's return to zero. This may have also solved that annoying rattle in the cluster that I could literally not put my finger on. Both screws were loose.

I hope this can help someone in the future before they rip their dash apart looking for a more complicated problem.

 

Very cool, glad you found it.