[Shotimes] braking problem???

[Shaun & Meggen Livermore]

I'll try to explain this as quickly and simply as possible! My car
drives completely normal while your driving. Then when you press the
brakes in a bout half way everything is fine. Once you apply more
pressure than that the car pulls very hard to the left and the steering
wheel turns to the right. I've done a lot of inspection and replaced
many parts but nothing has seemed to work. Any suggestions as to what
could be causing such a thing? Thanks!!