[Chaplin]

I would bet on sticky calipers. When you changed the pads and pushed the pistons back in the calipers, did they move freely?? Both sides? Did you clean and grease the pins that the calipers slide on??

Also you may want to take off each caliper, one side at a time, have someone press the brake pedal and make sure that each piston moves freely- but be careful not to allow the piston to move too far out or it may pop out of the caliper.

If, after checking the above, you still have problems, I would check the items Bob Putnam listed.

Good luck.