Those things are really bad about this... when the wheel speed sensors go bad, I've seen them take out the ABS actuator with it. There is actually a bulletin on this issue. The bulletin is #NTB07-016b. you have to grind a hole in the knuckle to allow debris to exit. The debris is what takes out the wheel speed sensor, which in turn takes out the actuator.
http://ww2.justanswer.com/uploads/ba...NTB07-016b.pdf