2004 HARLEY-DAVIDSON XL883 Wheels Problems

MY WIFE WAS RIDING HER MOTORCYCLE TO WORK AND HAD JUST LEFT OUR RESIDENCE. SHE WAS APPROACHING A CURVE IN THE ROAD AND WENT TO APPLY HER BRAKES TO SLOW DOWN BEFORE ENTERING IT. THE REAR BRAKE PEDAL FAILED WITH ABSOLUTELY NO PRESSURE. SHE WAS ABLE TO DOWNSHIFT, SLOW DOWN, AND SAFELY RETURN TO OUR RESIDENCE. UPON INSPECTING THE REAR BRAKE SYSTEM, WE COULD FIND NO OBVIOUS DEFECTS (NO LEAKS, FLUID FULL AND PROPER TYPE, PADS GOOD, AND CALIPER FUNCTIONING). INITIALLY WE THOUGHT THE REAR BRAKE PADS MAY BE TOO WORN (ALTHOUGH THERE WAS APPROXIMATELY 0.25" OF MATERIAL LEFT ON BOTH PADS) AND REPLACED THE PADS. AFTER THIS WAS DONE, WE COULD SEE THE CALIPER MOVE, THE PADS CONTACT THE ROTOR, BUT THERE WAS INSIGNIFICANT PRESSURE TO STOP THE REAR WHEEL. WE BEGAN RESEARCHING ONLINE AND DISCOVERED NUMEROUS PEOPLE HAVE REPORTED REAR MASTER CYLINDER FAILURE AFTER HAVING THE REAR TIRE...