Performance Indicator Gauge

Mattax said
Needs a 1/8" hose barb fitting like this. or did you just take that off during disassembly?
View attachment 1715539412

I beleive inside is a bourdon tube.

Yes the hose barb is in the picture at the top. I put a few drops of penetrating oil in it and it loosened up.
It moves left to right now.
I think you're right that it some kind of tube because it's not a screw.