Stopping

[92BIRD]

So i'm going about 55 down a road, green light for the left turn lane i want, so i keep my speed up, the guy in front of me was going fast, and is now hard on his brakes for no reason, so I come close to locking mine up, all well and good, no accident. But as I come around the corner to my house, I tap the brakes. and theres nothing, I put the pedal to the floor, and get maybe 20% of my normal stopping power, I checked the lines, no leaks, and i've been told it wouldn't be the master cylinder because those don't fail instantly, though the guy who told me could be wrong.

Also, my abs has never worked for as long as i've owned the car, and it seems to be a negative multiplier in my problems with the car, is there a way to completely shut down and remove the abs system from the car?

Any help is greatly appreciated.