Just like when you drive a car in real life, don't mash the pedal when you brake. I don't play with a wheel but when i apply about 75% pressure to the brakes, it's usually enough to bring the car down to speed. Try dong that for awile and if it doesn't work i'm sure someone will be along shortly to give you other advice.
Thats how I drive, but I just find that when its at 1, or 0, even a slight press on the brake yields a sliding back end.
Any good reading for this?
p.s. try googling: braking finesse, race car braking..............
I think the term you're looking for is "threshold braking". It's tough enough in a real car without ABS, I'd have no idea how to do it in a game with no brake pedal feedback.