DadsFirstPickup - Not sure if it's applicable to your line fitting and loose wrench fitting situation, but when I last replaced a couple of my brake lines (we fabricated them using tubing and new fittings), I found that the new fittings thread count/pitch were correct for my '51 existing parts, but the hex heads where metric and not standard inch measurement sized. I wonder if your tubing fittings succumbed to the same situation and are actually metric hex heads???
