I cant seem to get very much of a brake pedal on my Buick. The system is a generic under the floor power brake pedal kit with a corvette master cylinder and a 7" power brake booster. The rear is stock 2000 blazer disk brakes. The front are camero calipers. I have Wildwood 2 PSI check valves on both lines. the linkage from the pedal to the booster is adjusted to give as much stroke as possible. The rod between the booster and the master cylinder seems to be the correct length. I have bled and bled. I have brakes but only at the bottom of the stroke and not enough stopping power. Any suggestions????