My BMW 2003 530i jerks while braking. It is a single jerk/thud and it is around 10mph. This happens when I brake gently. If I brake hard, there is no jerk.
Car experiences a jerk/thud while braking/slowing down on 2003 BMW 530i
It's hard to know what this might be without personally driving and inspecting the vehicle, but my first thoughts are that something in the front suspension is worn out, it may be the thrust rod bushings, which are a common problem with this model.