Got antilock warning light two months ago. Tried to figure out which wheel sensor was bad and decided that the car having 190k miles, wasn't worth the effort. So I pulled the ABS module breaker. Since I did that, the pedal height and firmness has improved greatly. Still working great after 2 months. Conclusion. I never had a mechanic with a scan tool bleed the ABS module after I replaced master cylinder. Didn't want to risk them breaking something on a car this old.