Rebuilding TXV

[69-er]

I am rebuilding the entire system in my 66 Chevy truck and need to choose between buying an new TXV or attempting to rebuild it. The new ones aren't quite the same dimensionally so I am wondering about the feasibility of rebuilding it.

I would imagine the valve components would be the easy part. The unknown is if the diaphragm is still operating properly. I'm sure I could could vary the temp of the bulb to see if it moves. The question is how much should it move? Do these tend to leak over the years?

Thanks!