Hi I have a 2012 nissan versa 6speed, I was going to work today down a hill it was snowy/icy conditions when I went to apply the brakes to stop at the stop sign my peddle was hard as a rock and I could not stop so I did panic but I managed to pull over on the side of the road no traffic was coming so I took the turn I was only doing prob 5 km, but it also happened this morning at the end of my road which is flat when I went to stop at the end of the road peddle was hard as a rock but I managed to get out onto the other road it was quite scary. But then both times the braking was fine afterwards. But now and then on the drive it sounds like a grinding noise. Is this normal? Is it from the ABS anti locking braking system?