Agree with John W's comment about changing to dash 3 braided line and fittings. Copper lines work harden and crack, nylon lines can melt, and who wants all that precious
oil pumping out?
Also, if your connection at the engine end or guage end uses a fibre washer, swap this out for a rubber "O" ring. This of course could be purely an english thing - all our
oil pressure lines used a tiny fibre washer, and they all leak.