Some Heuer crowns are two part . The part where the stem screws in (pipe) is shaped like the decorative feet on a rack of Lamb . And that fit's into the crown proper ( signed Heuer bit ) secured with a rubber gasket . The rubber returns to the primordial slim which it came from and the crown will not work . Usually the crown can be replaced with a one part crown and can be found on line .

Good Luck

: I have a 70's carrera (cal 12) and the watch
: guy says the crown gasket is bad, but it is
: not possible to only replace the gasket.
: Says I need to source a new crown with a
: good gasket.
: This seems strange, I would expect you could
: replace a crown gasket much like a case back
: gasket?
: Can anyone help me understand the correct
: procedure?
: Thanks