92 240 ABS Soft brake pedal

[rwill52mg]

The brake pedal on my 92 240 is soft and seems to go almost to the floor. I inspected the brakes and determined the rear calipers were bad and replaced them with the addition of new pads and blead the brake lines. I thought I solved the problem, but the soft pedal is only slightly improved. One symptom I noticed is that when the ignition is off, and the brakes are slightly pumped the pedal is rock solid. At the moment in order to add more stopping power I have to use the emergency brake. What is the next step to solve this problem? Thanks