Hey guys,

So my car has been acting up for a while. Whenever i drive in reverse and hit the brakes (like backing out of a parking spot) , you can hear the ABS system and the brakes get really crunchy. I can push the brakes all the way down and the car will barely stop. If I work the brake then the ABS shuts off and it stops normally. I'm pretty sure its the rear brakes doing this, but its hard to tell.

It only does it in reverse. Is there a sensor or something else I should check? I cant remember when it started doing it, but I did have to drive over a really broken road a while back and it was kicking up all sorts of stuff.

Ideas???