leaking Brake lines

Someone mentioned fittings type. THIS IS IMPORTANT

You must be certain you are not mixing SAE flare and AN / JIC flare fittings.

SAE is 45 degree flare angle

AN / JIC is 37

Might help to lube the fittings before assembly. Research this, I think you need to use mineral oil, as some types of oil are not to be used with brake systems.