I think Wrenchbender has it here. I had similar problem years back. The rubber lines were swelled on the inside restricting flow. I replaced them and the brakes worked perfectly. I cut the old lines in-to, and the lines on one side were completely swelled together on the inside restricting flow. They looked good from the outside. You might want to check to see if you are getting fluid to that side before you start replacing hoses. I hope this helps.
Mark...
