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

A more common problem than many realize. Dead soft copper is a pain in the butt to stamp, and burrs easily. Harder copper will stamp nicely, but it does not deform to seal properly.

So, when someone goes to China for washers, they ask for cheap. Half the time the purchasing agent does not have a clue about what that washer actually does... So you get half hard copper, stamped & flattened. The cold working of the manufacturing process cold works it to nearly full hard. Much lower manufacturing cost, but the part is not to spec.

This is easy to fix. Copper anneals readily over 750f. Lay the washers down on a firebrick, and grab the propane torch. Heat them until they get to red hot, then walk away and let them cool. Dead soft now. They will have a thin film of black oxide, which you can wipe off with steel wool.

Take an old pair of washers from a used caliper. Anneal one. Now try to bend each one with your fingers.

B.