Somebody posted a tech tip about replacing the capillary tube assembly with one from an aftermarket gauge by cooling the bulb in an ice/salt mixture and cutting and splicing the tube near the original stovebolt dash gauge by soldering both ends into a close-fitting brass sleeve. It's an interesting concept, maybe worth a try one of these days if I can find a non-working temp gauge to tinker with. I'm thinking that a dry ice/alcohol cooling mixture might work even better to keep as much fluid as possible in the sensor bulb. The temperature of that mixture gets down to 40 degrees below zero or so. That's how we installed big bronze bushings in the tire curing presses I used to maintain. The bushing would shrink far enough to be a slip fit in a hole about 12" in diameter, then expand to be a very tight fit in the hot press housing.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!