Thanks for the picture. That helps. If the threads are stripped on that fitting, you have two choices, one I don't like, and the other the right way.
The right way is to replace the line. If you don't want to do that, purchase a new fitting, cut the steel line in two about 4" from the fitting, remove the old fitting, slide on the new fitting, and use a compression fitting to rejoin the steel line. Most parts stores will have all of the things you need. The fitting is a standard type fitting, so that shouldn't be an issue. The pipe is the tough one. They also make very high pressure hose that would be okay, but then there is the chance of it coming apart. If you do use the rubber hose, make sure to use fuel injector line clamps. They work the best and have the best chance of holding things together.
Let me know if I can help.
Thursday, May 16th, 2019 AT 6:08 PM