Hey Bob, I too think this may be a flaring tool issue. I have never had as much problem as Don is refering to. I would really suggest you move away from any form of sealing tape on a flared connection. The thread is only to apply pressure to the double flared end. The thread itself does NOT seal. Take a look inside the fittings to see if the nipple that the flare pushes onto is deformed. I like the idea of using a tee peice to bring your 4 way together. Also I would never use brass anywhere in a brake system, stick to steel only unions. Good luck.
Andy.