Repairing a tachometer

[tallyho8]

The tachometer on my Ford/New holland 4610SU was fluctuating wildly so bad it was unreadable. I priced a new one for $200 and decided I would try to fix the old one first. I disassembled it and found that there was extreme play in a bushing causing the fluctuation.

In the photo there is a small shaft about the size of a small sewing needle that goes into the marked hole. Evidently there was a bushing in this hole at one time but now the hole is 5 times the size of the shaft allowing it to wobble.

First I planned to silver solder the hole up and then drill a hole the necessary size in the center but dropped that idea because I had nothing precision enough to drill the hole exactly dead center. So I mixed up some epoxy and filled the hole and cut the end off a small paper clip and rubbed a little vaseline on it and stuck it in the center of the hole. When it hardened, I pulled out the piece of paper clip leaving a hole close to the perfect size and reassembled the tach.

It is working much better now but I have no idea how long my epoxy bushing will last. It is not perfectly steady because I probably didn't have the paper clip dead centered but it is good enough now.

Total cost: Part of my old tube of epoxy that costs $1.98.

[wushaw]

Have you tried lubeing up the cable since your repair.