[deliriousga]

That stinks. Sorry to hear about the screw head stripping.

Have you tried the re-balancing yet? If not, try that before you continue working on the sensors. I usually try balancing, then check the bearings and ball joints for play and go to the sensors if those aren't the cause. I clean the sensors at each pad change so that's usually not a problem for me any more.

As you said, the sensors have probably never been removed. With the other screws, put the allen wrench (sockets are better) in the screw and take a hammer and smack it with medium force several times to break up the rust that has formed on the threads. That gives it an impact wrench effect. Also, make sure the allen receptical in the screw is completely cleaned out and the allen wrench goes in all the way.