I replaced the steel lines and went through 3 calipers before we did the teflon tape. All three were bad in that case, and all three were from NAPA and after 3 months still no leak after the tape. I am paranoid as heck about my brakes, esp being a paramedic and seeing some of the crashes people get in. Granted most are BS minor fender benders, but the really bad ones make ya cringe. It seems that if I remember correctly, it was leaking at the flare, so that might be the reason it has worked. I don't know, I am definitely NOT a mechanic, I break things a whole lot easier then I fix them. And if I don't know, I will be the first one to ask a question.