Forcing the brass insert into the nylon brake line tube was difficult for me using the boiling water method. I found an easier way is to push the insert with a hot aluminum nail. I held the nail with vise grips, heated it in the center with a propane torch and pushed. Only a very small flame is needed. As soon as the insert starts going in, move away from the flame. Do not push the insert in too far or else the end of the tube will mushroom. Not much heat is required. Even a lighter or candle might work, but I did not try them.
Joe
Joe