I have seen alot of attempts at repairing them. Some were functional, but not very attractive. I'll be watching this thread. -Mitch
You could use the old formula JB Weld on the threads. It will not leak/But it will never be able to be removed either.....
Uncle max sells a brass insert that will fix them. That is the best fix. Or you can buy an oversized needle and seat @ vintagespeed.