What was found
(CAN) PRIOR TO PUSHBACK, FUEL SPILL OCCURRED FROM SURGE TANK VENT HOLE. NR 3 FUEL TANK OVERFILL DUE TO UNCOMMANDED FUEL TRANSFER. AIRCRAFT HAD JUST COMPLETED MAINT AND NR 3 JETTISON OVERRIDE PUMP HOUSING AND CHECK VALVE REPLACED. SEALS RUPTURED DUE TO OVERTORQUING OF SCREWS. SCREWS SHEARED AND BELOW CHECK VALVE. SEAL REPLACED AND VALVE PROPERLY TORQUED.