Wiper Seal Installation - JLG 400S Service And Maintenance Manual

2. Use a soft mallet to tap a new wiper seal into the appli-
cable cylinder head groove. Install a new retaining ring
and bearing into the applicable inside diameter of the
cylinder head groove.
Figure 5-22. Wiper Seal Installation
3. Place a new o-rings and backup ring in the applicable
outside diameter groove of the cylinder head.
O-RING
BACKUP RING
Figure 5-23. Installation of Head Seal Kit
4. Carefully install the cylinder head on the rod, ensuring
that the wiper seal, retaining ring and rod seals are not
damaged or dislodged. Push the head along the rod to
the rod end.
5. Using suitable protection, clamp the cylinder rod in a
vise or similar holding fixture as close to piston as possi-
ble.
6. Place a new o-ring in the applicable inside diameter of
the piston.
7. Carefully thread the piston on the cylinder rod, ensuring
that the o-ring is not damaged or dislodged and hand
tight. Secure using ball and setscrew.
8. Remove the cylinder rod from the holding fixture. Place
new piston seal in the outer piston diameter groove. (A
tube, with I.D. slightly larger than the O.D. of the piston
is recommended to install the solid seal).
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SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
O-RING
MAF00100
PISTON SEAL
Figure 5-24. Piston Seal Kit Installation
9. Position the cylinder barrel in a suitable holding fixture.
EXTREME CARE SHOULD BE TAKEN WHEN INSTALLING THE CYLINDER ROD,
HEAD AND PISTON. AVOID PULLING THE ROD OFF-CENTER, WHICH COULD
CAUSE DAMAGE TO THE PISTON AND CYLINDER BARREL SURFACES.
10. With barrel clamped securely, and while adequately sup-
porting the rod, insert the piston end into the barrel cyl-
inder. Ensure that the piston loading piston seal are not
damaged or dislodged.
11. Continue pushing the rod into the barrel until the cylin-
der head can be inserted into the cylinder barrel.
12. Screw the cylinder head into the barrel using a hook
spanner wrench and torque cylinder head to 549 ft. lbs.
(745 Nm).
13. Caulk at the machined area of the cylinder barrel end so
that it locks the cylinder head in place and it does not
unscrew from the barrel.
Figure 5-25. Caulking
14. After the cylinder has been reassembled, the rod should
be pushed all the way in (fully retracted) prior to the
reinstallation of any holding valve or valves.
15. Install the new o-rings and plugs into the cylinder port
block. Install the counterbalance valves in the rod port
block and torque to 30-35 ft. lbs. (41-47 Nm).
O-RING
MAF00110
MAF00120
5-55