Yes you have to bleed them if you disconect the brake lines. I prefer to disconect the lines at where they meet the hard lines. put a bowl or pan under the connection to catch the drips but not a lot will drain. After you have everything back together top off the fluid resevoir. then connect a tube and catch bottle to the top of the bleed screw on the farthest caliper from the master cylinder. With the bleed screw shut and a friend pump your brakes hard three time while holding the brake pedal to the floor on the third pump. While he is holding the brake pedal down crack open the bleed screw and watch the bubbles and fluid come out. Repeat this until you don't see any bubbles and then move on the next caliper farthest from the master cylinder. I perfer to use ATE super blue brake fluid. IF you want to completely flush your system which is a good idea if you road race your car, keep bleeding each caliper until the fluid turns blue. for bleeding I have a vacum pump with clear lines and an inline catch cup that you can buy at any parts store. If you use this this could be a one man job, but I still always like someone in the car to do a few pumps as mentioned above to make sure there are no bubbles whatsoever. Let me know if you this is clear or if you still have questions. One more thing, keep an eye on the resevoir and make sure you keep it full while bleeding. If you allow the master cylinder to suck air you are screwed and have to start all over. Also a few really hard pumps will ensure that there is no air in the ABS system.