Has anyone fixed their own speedometer??

[NHCharger]

Had my gauge cluster rebuilt for the 68.One year warranty. Of course that warranty long expired before I got the car running. Today at the 550 mile mark the speedo started acting up. The odometer still works fine and based on the threads I searched it is the speedometer head. I'm going to see this vendor at Carlisle so I'll see if he will still honor the warranty. If he doesn't is this something I can fix myself? Most of the threads recommended sending it out to get fixed.
Couldn't find any threads showing this fix.

I really don't want to take the dash apart right now. Will leaving this til winter cause anymore damage to the speedometer?

[XH29N0G]

How is the speedometer acting (bouncing needle?  wrong reading? or something else?) 

In some cases, the speedo is gummed up and this likely can be fixed.  If it requires calibrating but all else is OK with it, it is more involved, might be possible, but probably simplest to leave to a shop.  If there is something wrong with the clock spring or magnet, it is above my level of experience.

I learned a lot about the mechanism of the speedometer by breaking my own one, so I can tell you what not to do. 

Unless you really want to know about it, I would suggest sending to a shop.

[NHCharger]

Bouncing needle, wrong reading, won't return to zero all the time. Odometer works fine. No strange noises from the speedo cable which is new.

[XH29N0G]

I would talk to the vendor at Carlisle.  The mechanism is pretty simple, but is delicate. 

There is a hair clock spring that should move the needle back to zero if nothing is gummed or otherwise bound up.  There is a spinning magnet that causes a field that makes the assembly the needle and spring are on rotate. 

My understanding is that the issues can be it is gummed up or catching in some way, that the spring can go bad, or that some of the magnetics become demagnetized.  Provided the spring has not been damaged, the tension it provides can be adjusted - and this is how it would be calibrated by spinning at 1000 RPM (60 mph).   My guess is that the magnetics and the spring are likely OK since it was working after being rebuilt, and that there is something like dust gumming it up.  I suppose that something might have slipped and be binding it up, or that the spring may have slipped, but my first bet would be on something gumming up the works.

I (mostly) fixed one I had by immersing the head in isopropyl Alcohol and then spinning it with a drill in reverse a few times.  Keep in mind that there are people on here who know a lot more about this than me, and my ultimate resolution of speedometer issues was to buy a replacement.