Pontiac Repair: rear brake line on 97 grand prix, double flares, flaring tool

Question
i have a leak in the rear brake line on my 97 grand prix.it is in the section that runs underneath a frame piece right behind the gas tank,running from side to side.
what is the approx length and diameter of this piece so i can replace it  

Answer
It is 3/16 brake line but you will have to determine how much needs repalcement and section it in accordingly with double flares and unions. This cannot be done with compression fittings or rubber hose because that will not handle the pressure your brake system devlops. If you don't have a flaring tool you can get one for less than $30 at a parts store but I would recommend having it done by someone who has used one before. Making a good double flair takes a lot of practice and it can be potentially life threatening if not done right because you could loose brake pressure rapidly.