hydroboost diagnosis test

Joe I would start with the simple things first. Look at the entire brake system for leaks. Look at all the lines calipers, MC, etc. Fix any leaks before bleeding brakes. I gravity bleed mine by jacking up the front end and starting with the bleeder farthest from the MC then one by one until you get to the closest one. Open bleeder and let it drain into a glass jar when you get all the dark fluid out and clear fluid is draining close the bleeder and repeat the other 3 wheels. While you are draining you need to add new fluid to the MC and keep it full so no air gets into the new fluid. Check your pads to make sure you have at least 1/4 in left and they are not glazed over which would make it more difficult to stop. The rubber lines that Golden HVAC is talking about are attached to the metal brake lines and go into the caliper when they get old sometimes the cord fails inside and they balloon out making the brakes spongy. Also as the age the rubber swells inside the metal attach points and as it swells the metal constrains the rubber and closes the inside dia and it acts as a check valve. Mine were causing the MH to pull to the left at 16 tears old when I applied the brakes,yours are probably past due.