2000 VW Beetle. I have a low brake pedal which makes me feel as if the fronts are working and the rears are not. I can manually bleed the brakes and fluid comes out all wheels. All pads have been replaced recently and I just added a new rear caliper. The problem was there before opening the system to replace the caliper. If I hook my Vag com up and trigger the ABS unit the pedal comes up nice and hard. Of course when I restart the car the pedal is gone. Is there a proper adaption program or something for the brakes after the battery has been disconnected for a period of time. My Bently book is vague in this area. I replaced the master cylinder as it felt like one of the pistons was bypassing. I bench bleed the master with plugs to dead end it. I had a nice hard piston on the bench. I am leaning toward something in the ABS control unit having air.When energizing the ABS with the Vag, it showed to bleed the front brakes. As I cycled through the groups, I did not find a group that pumped the ABS and asked to bled the rears. i think this is what is needed. Thanks in advance for any input.