Are banjo bolts grade 8?

Sometimes, I have seen where the new copper seal rings are too hard . The problem is they won't crush. If you have access to a fuel injection pump shop or truck shop nearby take your seal rings to them as samples. Tell em you want the same ID rings. The ones they commonly use for turbo oil supply and fuel are much softer than the junk rings that come in the rebuilt caliper box. Of course this is last option after everyone else's ideas have been tried. I believe everyone else has given you good solid guidance. One last thing is be sure to check the radial grooves in the head of the flex line , any damage there and you'll never seal properly. Just my 2cents