OK guys, what is going on with my '81 733i automatic's brakes? When I press the brake pedal slowly (like in a parking lot looking for a space) it will go to the floor then stop the car. Very little or no resistance at all untill it his bottom. It doesn't "pump up" if I pump it slowly, it just goes down to the floor with each slow pump. If at any time I press the pedal quickly (quick stop or panic stop) it stays firm and high stopping the car as well as it should. The accumulator and brake pads( all caliper pistons move smoothly) have been replaced but no change in pedal action. What to check next?