this is regarding break

I always had problom with the break of the above car. the problom is that when i suddently stop the vehicle,the vehicle tends to vibrate and can not stop properly.however i have checked the break system(ABS) and also put brand new break pads.but problom remains.no proper breaks when wheical run fast and break sudduntly. please answer me.

New the brake discs machined or replaced. had the same problem with my old pulsar