What was found
(CAN) DURING ACCEPTANCE, TEST PROCEDURE, ATP, OF A RETURNED BCV, NO PRESSURE WAS DETECTED ON BRAKE LEFT, BL, PRESSURE PORT. THE INVESTIGATION REVEALED THE ORIFICE PLUG THAT IS PRESSED INTO THE SLEEVE END CAP ASSY WAS DISLODGED AND SUBSEQUENTLY BECAME TRAPPED IN THE FIRST STAGE BETWEEN THE HOUSING AND THE ARMATURE ON THE RETURN SIDE. UNIT WAS REWORKED AND RETURNED TO SERVICE. POTENTIAL QUALITY ISSUE CAN EXIST ON IN-SERVICE AIRCRAFT.