JLG 400S Service And Maintenance Manual page 320

SECTION 4 - BOOM & PLATFORM
10. Looking from the angle shown, rotate the piston (3) until
the marks you put on the piston and the housing (1)
during disassembly line up as shown. Using a rubber
mallet, tap the piston into the housing up to the point
where the gear teeth meet.
11. Looking from the opposite end of the housing (1) you
can see if your timing marks are lining up. When they do,
tap the piston (3) in until the gear teeth mesh together.
Tap the piston into the housing the rest of the way until
it bottoms out.
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12. Install the shaft (2) into the piston (3). Be careful not to
damage the seals. Do not engage the piston gear teeth
yet.
13. Looking from the view shown, use the existing timing
marks to line up the gear teeth on the shaft (2) with the
gear teeth on the inside of the piston (3). Now tap the
flange end of the shaft with a rubber mallet until the
gear teeth engage.
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