What was found
(CAN) PIC REPORTED ABNORMAL SUCTION INDICATION, AUTO-PILOT ISSUES, FLIGHT NAVIGATION INSTRUMENT INDICATION ISSUES. GROUND FUNCTION TEST OF THE VACUUM/PRESSURE SYS WAS PERFORMED AND RELIEF VALVE WAS FOUND TO HAVE SEVERE SPRING WEAR, VALVE SEAT DAMAGE AND GUIDE WEAR. THE HOUSING WAS ALSO WORN SEVERELY. SYSTEM WAS INSPECTED IAW WITH MANUALS. ALL TESTS WERE PERFORMED IAW WITH MANUALS WITH NO OTHER ABNORMALITIES DETECTED. ALL OPERATING PRESSURES WERE VERIFIED PROPER.THIS PART WAS INSTALLED 605 HRS AGO FOR SAME ISSUE.