I'm helping a friend restore the brakes on their Datsun 2000 and after replacing the front caliper halves, the rear wheel cylinders, the master cylinder, the brake hoses, and replacing one section of brake line that runs midway of the car to the back, we have a spongy pedal. It feels like there is air in the lines, but we've bled and bled and bled. Just for grins we took the porportioning valve apart and cleaned it (it was the only thing we hadn't touched), but it made no difference. We tried a power bleeder as well that works off of a compressor hose and hooks up to the bleeder screw, but still a spongy or bouncy kind of pedal - not rock solid. If we pinch off the rubber lines then we get a real solid pedal. Being that he got the car with the brakes all dry rotted and shot, he doesn't know how the pedal is supposed to feel. It's just not what I would call normal, but we don't know anyone else with a 2000 to compare it to. Can anyone shed any light on this or ever experience this before??