Make sure that the pads are properly seated (i.e. that they aren't "off the track"). This can cause your brake fluid reservoir to overflow and the brakes to feel really soft after a pad change. Don't ask me how I know...

"When I'm in a slump, I comfort myself by saying if I believe in dinosaurs, then somewhere, they must be believing in me. And if they believe in me, then I can believe in me." - Mookie Wilson