I've seen a procedure for repairing the bulb-sensor gauges by super-cooling the liquid inside one of those cheap aftermarket gauges in a dry ice/alcohol mixture, and solder-splicing the new bulb and tube assembly onto an original gauge. I've got an old gauge on hand with a bad tube that I'm planning to experiment on.
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!