fob industries

I have a 2001 f250 7.3 4x4 w/ 210,000 miles. Just replaces master cylinder, front rotors & front pads. Brake pedal still going to floor after a stop. Had new master cylinder replaced and bleed lines again. Same problem exists. Told brake lines look okay and could be ABS Valve sticking. Expense part for a maybe! Can this part be serviced/rebuilt or does unit get replaced. Thank You, Marci Sadowsky