Autozone or any parts store sell both types of line, GM uses and ISO(bubble flare) and metric flare nuts on the lines. Make sure you can open your bleeder screws or you may also need wheel cylinders or calipers. On lines I replace, I cut them off at the hydraulic unit, be it a wheel cylinder or a flex hose and use a 6 point socket to remove it. There are two types of line sold now, one has a rust preventing coating and one does not. It depends on how long you plan to keep the car. But even non treated lines last many years!