Speedometer not spinning freely after rebuild

[Luke's02]

My speedometer was not working so I decided to take it apart to figure out what was wrong. Turns out that the shaft that goes into the drive mechanism had a slight bit of rust on it causing enough friction for it to not spin freely. Once I cleaned everything up and added fresh grease I put it together.

 

The problem I am having now is that when I spin the shaft by hand, the speedometer needle will go all the way up to 120mph.

 

I confirmed the speedometer needle return spring is working because I tested it without the mechanism on. I am also aware that the tiny needle that fits into the end of the shaft is very delicate however it looks perfectly straight to the naked eye.

 

I have looked all over to see if anyone has the same problem and im at a loss. I'm just wondering if anyone has ever had this issue after putting a speedometer back together, and what a possible fix could be? 

Edited May 3 by Luke's02
Image attachment

[dlacey]

The alloy cup/spring/needle should be just 'floating in space', with nothing making mechanical contact - its just Eddy Currents who does all the work. The common fault on these is that the spinning magnet becomes loose and moves forward to make mechanical contact with the alloy cup... then the needle gets pushed all the way round to its end-stop.  Repair is to push the magnet back on to its driveshaft, sometimes with addition of some threadlock to stop it happening again.

[Luke's02]

Thank you for the reply. I did as you said and I believe the issue is that the pin is just a little bit too tight when putting it through the hole causing friction and therefor the alloy cup is not floating

[Luke's02]

Fixed it! I just had to take a sewing needle and round out the hole a bit so the pin went in without friction.