I don't know about the grooves, but to get the wheel off, you might try to stand on the lug nut wrench to put your weight on it. Hollow pipes from household items like broom handles can also work as extensions. Other than that, a stop at a tire and suspension shop could yield some relatively cheap "insides".
Without knowing the miles though, its hard to make any suggestions on the rotors, discs or sensors but the light is there for a reason. Have it checked out.