JLG 15/20MSP Service Manual - Manual (Page 103)

SECTION 5 - MAST COMPONENTS
3121231 – JLG Lift – 5-13
Cylinder Assembly
(See Figure 5-4.)
1. Rinse the inside of the tube with hydraulic fluid and
allow to drain. A high-pressure rinse followed by a
wipe with a lint-free rag is preferable. Clean all inter-
nal components of any foreign material.
2. Lubricate the head and all seals with hydraulic fluid
prior to installation. Install the seal, wiper, o-ring,
back-up ring, and retraining ring to the cylinder
head.
3. Lubricate the piston and all components with
hydraulic fluid. Install the seal and wear ring to the
piston.
NOTE: Re-check that seals are not twisted or pinched and
are properly seated.
4. Place the rod on a clean table. Install the static pis-
ton o-ring seal into the groove on the piston end of
the rod.
5. Install the head followed by the piston onto the rod
noting the proper orientation of each component.
Torque the piston nut to 100-120 ft. lbs.
6. When the rod assembly is ready to be installed into
the tube, liberally apply an anti-seize lubricant to the
cylinder head surface which slides into the cylinder
tube.
7. Next dip the entire rod assembly into hydraulic fluid
and stuff this assembly into the tube. Watch the
seals as they pass over the rod port (if visible) to be
sure they are not nicked or cut.
8. Install the head until the retaining ring seats in it’s
groove.
Cylinder Installation
To install the lift cylinder reverse the Lift Cylinder Removal
instructions at the start of this section, however perform
the following additional steps during re-assembly.
1. Apply Loctite #222 (purple) and torque to 85 ft. lbs.
the cylinder mount shoulder screws securing the lift
cylinder mount halves together at the bottom of the
mast.
2. Check that the platform electrical control cables and
the sequence cables are seated in their sheave
wheel assemblies when extending mast sections for
reassembly.
3. After assembly, readjust the chain at the bottom of
mast section-3 and apply Loctite #242 to the lock
nuts before final tightening.
4. Remove the plastic from under the hydraulic reser-
voir tank cap.
Figure 5-4. Lift Cylinder Component Cross-Section
(MVL/MSP).
1. Cylinder Rod 6. Apply Anti-Seize 10. Piston
2. Cylinder Head 7. Cylinder Tube 11. Wear Ring
3. Rod Wiper 8. Spacer 12. Piston O-Ring
4. Rod Seal 9. Piston Seal 13. Piston Lock Nut (a)
5. O-Ring
Note: (a) Torque 100 - 120 ft. lbs.
1
3
4
5
6
8
9
12
10
11
13
2
7