Do you have any pics of the parts that you are talking about.The reason I ask is they dont sound like they are brake fittings other than the residual valve that you mentioned.As in above posts there is no sealer avalible for any brake parts.Most of all lines and fittings have a normal flare or a bubble flare.Those flares are what makes the seal.If for any reason you have any dought on what you are using get rid of it.The last thing you want is to be out cruising and loose your brakes and hurt yourself or someone else.Brakes are serious stuff when building a rod
JMO