Left side front brake failed at the spring fling. Put a bolt in and rode home on one disc - nice firm feel. I have replaced the piston seals and dust seals on both front calipers. Cleaned them up and removed dirt and corrosion in the seal groves and installed new pads to both sides. I bled the right side with a mity vac and it seemed to bleed as expected. Tried many times to bleed the left side, one bottle of DOT 4 later still sucking many large air bubbles. The lever is spongy and comes very close the bar. It will firm up some if I pump the lever a few times. Any suggestions? Is it possible the air is sucked in by the new seals? There is no brake fluid leak.