What was found
THE NR 2 HYDRAULIC SYS RETURN FILTER BYPASS INDICATOR WAS FOUND EXTENDED (POPPED) ON PREFLIGHT CHECK. WHEN WE REMOVED THE FILTER TO CHANGE IT, A SMALL PIN WAS FOUND IN THE FILTER BOWL. UPON FURTHER INVESTIGATION, A HOLE WAS FOUND ON THE SIDE OF THE BYPASS INDICATOR. WE INSPECTED A NEW BYPASS INDICATOR AND DETERMINED THE PIN THAT WAS FOUND IN THE FILTER BOWL SHOULD BE INSTALLED IN THE HOLE IN THE SIDE OF THE INDICATOR. RECOMMEND STAKING THE PIN AFTER IT IS INSTALLED IN THE SIDE OF THE INDICATOR.