I did the brakes a while back on my wagon as one caliper was dragging - replaced calipers, rotors and front hoses - seemed like the master cylinder wasn't holding - could lock the wheels but holding pressure on the pedal caused it to slowly sink down. I assumed the master cylinder seal was leaking and ordered a new one which sat in the garage for a few months. Put it in today and bled only the bleeders on the front left thinking that would be adequate, and did see significant air. Nonetheless the pedal behaves about the same - constant pressure causes it to slowly 'sink' after the point where the calipers seem expanded. It doesn't feel like air, from what I remember of other situations. Any thoughts? Thanks in advance. Joe