So I'm experiencing a brake bleed mystery on my '98 4runner. I replaced the master cylinder and couldn't get the brake to bleed properly. We thought maybe Autozone had sold us a bad part so we took the new master cylinder back and exchanged it. Still the same problem. Not seeing any evidence of a blown wheel cylinder. No leakage and nothing but clear, bubble free fluid coming from all 4 bleeder screws. Going to try tightening up the rear brake shoes tomorrow. Any thoughts on why I still have a spongy brake pedal?