JB weld Epoxy is the answer. On my 1999 455: I removed, cleaned & dried fittings with Berkable 2+2. Then put a lite coat of JB Weld epoxy. Let set for 24hrs. No more problem.
JPC
Just had this happen with my 955, except the fitting didn't pop out... just got loose and allow a slow diesel leak. I had to do a quickie repair with what I had on hand which was Right Stuff RTV. Pulled the fitting out, cleaned the surfaces and reassmebled with Right Stuff. Holding so far. If the RTV fails, it will get JB Weld.