[fastfredracing]

Did you start with the wheel farthest from the master cyl??. You may have to let some air back into the front brakes, till they get soft again, and then bleed the hell out of the right rear, left rear, and move on to the front right , front left etc.. I have had quite a few cars in the past that just were a sob to bleed.
It is also possible that the caliper slides are frozen, and not allowing the front side of the caliper to meet with the rotor, so the piston comes way out hits the rotor, and when you let off of the pedal, it retracts, and takes a whole of pedal to bring it back into contact with the rotor. Is your pedal firm but low, or is it actually spongy and soft??. Also there may be an adjustable rod that connects the booster to the master. If you get a firm pedal that is low, and all else seems o.k. you can try to lengthen the rod a little bit( not absoutely sure if your volvo has this )