locking brakes can be down to shit tyres(often the case) worn brakes sometimes(rears ineffective) or your suspension being nackered, you just have to feel when they are going to lock and hold it there or back off. ive only driven a few abs cars and i far prefer non abs all the way!!!!

good luck with the brake swap, i personally recommend a full swap, you can see what state your full system is in,(mine was dangerous!)