JLG 510AJ Service Manual - Manual (Page 212)

SECTION 4 - BOOM AND PLATFORM
4-14 – JLG Lift – 3121181
11. Before removing piston (3), mark housing (1) ring gear in
relation to piston O.D. gear. There should now be timing
marks on housing (1) ring gear, piston (3) and shaft (2).
12. To remove piston (3) use a rubber mallet and a plastic
mandrel so piston is not damaged.
13. At the point when piston gear teeth come out of
engagement with housing gear teeth, mark piston and
housing with a marker as shown.
14. Remove O-ring (204) and backup ring (207) from end
cap (4). Set aside for inspection.