Ron:

I have the same model as you, more or less and have been down this road.

After removing the 5mm allen head, I sprayed PB Blaster all around the sensor and started twisting it left-to-right and vice-versa. I'd spray a little bit more at it as it loosened and eventually it worked itself out. It took awhile.

Once out, I sprayed the business end where the build up is with brake parts cleaner.

The drivers side was filthy; the passenger side was fairly clean.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"