Les - many of these planes I see have their original flex fuel lines. You can do chin ups on these ďflex linesĒ they are so stiff. They are petrified. Mil spec or not, if the lines are no longer flexible, they are junk. IMHO they should be replaced every 10 years. Once you cut them to get them out, look at the inside. Iíve seen them literally falling apart. You may want to look at all the lines in the plane.