Brake Problems

ok , what else is new with these wonderful braking systems on this car. well since i bought this car i have had issues with the brakes, the abs comes on whenever it feels like it. i'll be stopping and the abs kicks in and the car instantly stops so hard. then the pedal get's soft. once that happens its starts acting all retarded on me. the brake pedal feels like it slips and gets soft then it comes back ok. No fluid loss, new lines new complete front to back. Tonight the abs light came on.. usually when i turn at 1mph the car kicks into abs mode for no reason. then sometimes the back brakes let go while stopping and the car jerks forward cause the pressure gets dropped from the back and then of course abs kicks on. what the hell is the issue, when i replaced everything its been ok for 6months and now it started again.. should i disconnect it and say goodbye to abs, or is it a simple fix? what would the abs unit cause the pedal to soften so greatly then be normal after a second? Anyhelp would be awsome.. Thanks