Why does brakes lock up on 2005 Chevrolet Malibu

Replaced rear calipers pads and rotors the same on front when removed line no fluid came out ''thought was weird'' replaced, bled out fine.Also replaced master cylinder still locks up. started driver side rear now driver side frontlocks up

Asked by for the 2005 Chevrolet Malibu
you need to bleed the brakes