HAVING TO HAVE A DRIVE WHEEL REMOVED TO REPLACE A DEFECTIVE ABS SENSOR REVEALED A BADLY WORN ROTOR. FURTHER DIS-ASSEMBLY REVEALED A PAD WORN TO THE METAL(THE OTHER PAD ON THIS ROTOR WAS LIKE NEW). SEEING THIS, THE DECESION WAS MADE TO CHECK THE OTHER SIDE. IT TOO WAS EXCESSIVELY WORN AND THE ROTOR HAD TWO CRACKS IN IT. FULL DIS-ASSEMBLY OF THE BRAKING SYSTEM REVEALED THAT THE GUIDE PINS WERE CORRODED, CAUSING THE CALIPERS TO HANG-UP AND DRAG. ALSO, THE (2) FITTINGS ON THE CALIPER HOUSING HAD NEVER BEEN GREASED, NOT ALLOWING THE PADS TO "FLOAT" AS REQUIRED. HAVING THE ENTIRE SYSTEM DOWN, IT WAS DECIDED TO REPLACE ALL BEARINGS,RACES, AND SEALS, IN ADDITION TO NEW PADS,ROTORS, AND GUIDE PINS. BOTTOM LINE;;$3200+. THE GUIDE PINS THEMSELVES COST $450! ACCORDING TO THE TECHNICIAN AT TRUCK CENTERS(FREIGHTLINER) THE WHEELS SHOULD BE REMOVEDE EVERY 2 YEARS AND THE GUIDE PINS LUBED WITH NEVER SEIZE. I MAKE THIS POSTING, HOPING IT HELPS OTHERS AVOID THIS PROBLEM.