What was found
INFLIGHT AFTER TAKEOFF WE GOT MULTIPLE PARKING BRAKE ON INDICATIONS WITH EICAS CAUTION MSG PRKG BRK NOT RELEASED. IT WENT AWAY AFTER 1 HOUR OF FLIGHT TIME. EMERGENCY DECLARED PRIOR TO LANDING CORRECTIVE ACTION: PERFORMED TROUBLESHOOTING PER FIM 32-41-00-810-863-A. PERFORMED CHECK OF THE EMERGENCY PARKING BRAKE INDICATIONS PER AMM 45-45-00. INDICATION CHECKS FOUND GOOD. PERFORMED ELECTRICAL CHECKS PER FIM. ELECTRICAL CHECKS FOUND GOOD. PERFORMED OPS CHECK OF THE EMERGENCY/PARKING BRAKE SYSTEM PER AMM 32-44-00. OPS CHECK GOOD ALL BRAKE PISTONS OPERATE CORRECTLY. FAULT COULD NOT BE DUPLICATED.