What was found
ON TAXI OUT OF KMEM, SET PARKING BRAKE AND NOTICED LEFT AND RIGHT BRAKE PRESSURE INDICATORS SHOWING 0 PSI. AIRCRAFT STARTED TO ROLL FORWARD. APPLIED TOE BRAKES AND BRAKE PRESSURE BEGAN TO RISE TO APPROXIMATELY 500 PSI ON BOTH SIDES OF BRAKE PRESSURE INDICATOR AND AIRCRAFT STARTED TO JERK. TOE BRAKES APPLIED AND PARKING BRAKE RELEASED. NO ECAM, ALL THREE HYDRAULIC RESERVOIRS ALL INDICATE SMALL UPPER GREEN ARC. REVIEWED QRH. PER MAINTENANCE ON 122.775, ATTEMPTED CIRCUIT BREAKER RESET ON 133VU PANEL CIRCUIT BREAKERS T56 AND T51 WHICH WERE UNSUCCESSFUL. FOUND PARKING BRAKE SELECTOR (3309) OUT OF ADJUSTMENT. ADJUSTED SELECTOR REF ABOVE. PARKING BRAKE OPS CHECK AND INDICATION OK. FOUND PARKING BRAKE SELECTOR (3309) OUT OF ADJUSTMENT. ADJUSTED SELECTOR REF ABOVE. PARKING BRAKE OPS CHECK AND INDICATION OK.