i "blew out" a front brake line and decided to have the local napa store make me one to replace it. it leaked on both ends, at the hose and at the master cylinder. i thought it may have not been flanged correctly so I broke down and order a whole set. i tried to replace that same line again with one from the new set and itleaked on both ends as well. the brake hose and master cylinder are new however the block to the back of the mc is not. the connections were not leaking prior to the line rupturing. the connections on the new lines are brass. the connections on the old lines do not appear to be brass. is there a sealant that can and should be used or do i have other problems? I have not attempted to replace any of the other lines since i am having problems with the first one. Any ideas for a solution?