I have a buddy who is an aircraft tech. He told me they repair leaks in aircraft steel hydraulic lines by cleaning up where a pinhole is back a couple inches from the pinhole, then wrap with bare mechanics wire, then silver solder it. I've looked for videos on this procedure but have yet to find any info on it.
I have a line on my Bobcat that has rubbed enough it also has a pinhole in it. I'm about a half notion to try this type of repair. If it doesn't work, I have a local hydraulic shop that does make new metal lines but have no idea of cost. And the guy that makes them only does it a couple days a week, so I'd have to call ahead and see when he is available to make on.
I already took it off once and took it to them, and at that time he was on vacation. Didn't have the wire or solder to attempt it at the time so put it back on. Not the easiest place to get to for an old guy, but things have slowed since it's coming wintertime, and have a little extra time to work in the shop.