the ABS sensor on my passenger front is not working. i tried to remove the sensor, but it is stuck firm inside the hub. any ideas how to remove it? i can remove the 10 mm bolt holding it in, but the sensor itself will not budge an inch. I'm assuming that it is just a case of removing the bolt and pulling sensor up and out. am i missing something like a small grub screw? any ideas/ suggestions would be appreciated.