What was found
AFTER RECEIVING TAXI INSTUCTIONS, TOE BRAKES APPLIED & RELEASED PARKING BRAKE. BRAKES SLIGHTLY SPONGY. ACFT BEGAN ROLLING WITHOUT RELEASING BRAKES OR POWER. RECEIVED AUDIBLE BRAKES FAIL. APPLIED MORE FORCE ON TOE BRAKES. NO CHANGE, PULLED EMER BRAKE & STOPPED ACFT, PUT ENGS BOTH TO STOP. ACFT MOVED APPROX 2-3 FT FROM INITIAL POSITION. PULLED UP HYD SYNOPTIC WHILE SIC WENT OUT & CHOCKED ACFT. COULD SEE PTCU PUSHING PRESSURE TO LT SIDE SYS. ALL PSI ON INBD & OTBD BRAKES 2700 PSI. TEAM 700 PROVIDED AN ARES REVIEW, STATED REASON BOTH HYDS SYS DID NOT HAVE 3000 PSI WITH ENGS RUNNING, BOTH HYD PUMP SWITCHES WERE NOT IN NORMAL POSITION. POWERED ACFT & APPLIED PARKING BRAKE WITH PRESSURE FROM PTCU. VERIFIED ALL BRAKE PRESSURES GOOD VIA CDMS. STARTED BOTH ENGS & VERIFIED HYD PRESSURE AT SYS A & B WERE AT 3000 PSI ALONG WITH BRAKE IND PRESSURE BEING AT 3000 PSI. BRAKES FELT NORMAL & NOT SPONGY. BRAKES OPS NORMAL, NO DEFECTS. NO LEAKS. ACFT RETURNED TO ORIG CONFIG IAW AMM 32-41-00.