What was found
ATB, HYD SYS 4 QTY INDICATION LOW #4. A/C ARRIVED WITH 0.75 ON THE #4 HYD SYS. PLACED LOAD ON SYS WITH NO VISUAL HYD LEAKS ANYWHERE AND A STEADY QTY IND SYS 1 & 2 ARE AT 1.20 AND 3 AT 0.97.(<P>R/R THE CORRODED PIN, CLEAN & RECONNECT. C/W FLUID TRANSFER PER AMM 12-12-00. PIN RECONNECT CORRECTED ISSUE. TOP OFF HYD, MX READY.</P>)