I recently got a 94 GMC Sonoma that has been setting for 4 years. The brake pedal went to about 1 inch from the floor with marginal stopping power. I bled the brakes with no change. I then changed the master cylinder and now the pedal goes down about 2 inches with so-so brakes then slowing drifts to about 1 inch from the floor. There are no visible leaks in the system. Any idea what I should do next?
Sononma brake problems