Okay, here's what I'm working with. A late model aluminum master cylinder. The front port doesn't want to seal. Previously, with the original lines, it sealed fine.
I added an adjustable proportioning valve and had a local shop flare me a new line to attach to the front port. It didn't look quite right, but they assured me it would work. It leaked.
I decided to get rid of the line they flared and install an adapter fitting for the port and run a pre-made line out of it. It's still leaking.

So, I'm thinking their flare boogered up the male side in the master cylinder and it won't seal now. Are there any tricks "re-form" it? Or do I need to get a new master?

Thanks for any help. This is supremely frustrating.