Grinding from front of car

[ahlem]

I had the same issue. The wheel speed sensor on one of the wheels had accumulated enough iron filings to interrupt the signal occasionally. I took off all the sensors and stuck a bamboo skewer with a thin strip of non metallic Scotch Brite with some evaporative cleaner on it. I rotated the rotors and rubbed off the remaining filings that were stuck in there and blew compressed air down the holes while I rotated the rotors further. I used a white cloth initially to see how much gunk was on the sensor contact faces. it solved the problem for me. In my case it was like one of the brakes had locked up. Very annoying.