Why does my car not roll back when in neutral after doing a brake job and the car is not running

It is the right rear well that we change the spindle on because the outer bearing froze up and cause the wheel to stop spinning and came off, so now that we did a rear brake job it is the right rear break that ( I believe) Hasbro's up and cause the car not to roll backwards. Do you have an answer for this if so thank you very much it is the only car I have to get me from point A to point B