Ok I goofed with my last response so it went to a wrong thread. or at least it appears that happened.
Looks like a brass to steel coupling. the two metals have different coefficients of expansion as they get hot/cold. so the connection can fail under pressure.
I'd replace the steel parts with brass and the proper tape.. Precise length is not important only the diamater and thread.
Second that looks to be a "Home brew" Fix for a problem that likely did not exist. Some of the Home brew things I've seen seriously scare me.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times