What was found
MDIS 722 32-44 2658 12MAY22 MEM OPEN U PER FLIGHT CREW: ON TAXI OUT, HOLDING SHORT OF RUNWAY, PARKING BRAKE WAS SET AND INDICATED PARKING BRAKE ON ON ECAM, HOWEVER WHEN BRAKE PEDALS WERE RELEASED A/C MOVED FORWARD. RECYCLED PARKING BRAKE 4 TIMES BUT PROBLEM PERSISTED. RETURNED TO GATE. FACT 12MAY22 20:36 MEM REMOVED AND REPLACED PARKING BRAKE SELECTOR VALVE (3309) REF AMM 32-45-12-04. OPS CKS AND LEAK CKS GOOD. OK FOR SERVICE. PER SDR , THE MANUFACTURER OF THE VALVE IS MESSIER - HISPANO.