JLG 10MSP Service And Maintenance Manual page 37

SECTION 5 - MAST COMPONENTS SECTION 5 - MAST COMPONENTS
Lift Cylinder Component Inspection Lift Cylinder Component Inspection
Cylinder Rod Cylinder Rod
There should be no scratches or pits deep enough to There should be no scratches or pits deep enough to
catch the fingernail. Pits that go to the base metal are catch the fingernail. Pits that go to the base metal are
unacceptable. Scratches that catch the fingernail but are unacceptable. Scratches that catch the fingernail but are
not to the base metal, less than not to the base metal, less than 0.5 inch long and primarily
in the circumferential direction are acceptable provided in the circumferential direction are acceptable provided
they cannot cut the rod seal. Chrome should be present they cannot cut the rod seal.
over the entire surface of the rod and the lack thereof is over the entire surface of the rod and the lack thereof is
unacceptable. In the event that an unacceptable condition unacceptable. In the event that an unacceptable condition
occurs, the rod should be repaired or replaced. occurs, the rod should be repaired or replaced.
Cylinder Head Cylinder Head
Visually inspect the inside bore for scratches or polishing. Visually inspect the inside bore for
Deep scratches are unacceptable. Polishing indicates Deep scratches are unacceptable. Polishing indicates
uneven loading and when this occurs, the bore should be uneven loading and when this occurs,
checked for out-of-ro checked for out-of-roundness. If undness. If out-of-roun
exceeds 0.007", this is unacceptable. Check the condition exceeds 0.007", this is unacceptable. Check the
of the dynamic seals (wiper, rod seals) looking particularly of the dynamic seals (wiper, rod seals) looking particularly
for metallic particles embedded in the seal surface. It is for metallic particles embedded in the seal surface. It is
normal to cut the static seal on the retaining ring groove normal to cut the static seal
upon disassembly. Remove the rod seal, static o-ring and upon disassembly. Remove the rod seal, static o-ring and
backup and rod wiper. Damage to the seal grooves, par- backup and rod wiper. Damage to the seal grooves, par-
ticularly on the sealing surfaces, is unacceptable. In the ticularly on the sealing surfaces, is unacceptable. In the
event that an unacceptab event that an unacceptable condition occurs, the head le condition occurs, the head
should be replaced. should be replaced.
Piston Piston
Visually inspect the outside surface for scratches or pol- Visually inspect the outside surface for scratches or pol-
ishing. Deep scratches are unacceptable. Polishing indi- ishing. Deep scratches are unacceptable. Polishing indi-
cates uneven loading and when this occurs, the diameter cates uneven loading and when this occurs, the diameter
should be checked for out-of-roundness. If out-of-round- should be checked for out-of-roundness. If out-of-round-
ness exceeds 0.007", this is ness exceeds 0.007", this is unacceptable. Check the con-
dition of the dynamic seals and bearings looking dition of the dynamic seals and bearings looking
particularly for metallic particles embedded in the bearing particularly for metallic particles embedded in the bearing
and in the piston seal surface. Remove the seals and and in the piston seal surface. Remove the seals and
bearings. Damage to the seal grooves, particularly on the bearings. Damage to the seal grooves, particularly on the
sealing surfaces, is unacceptable. In the event that an sealing surfaces, is unacceptable. In the event that an
unacceptable condition occurs, the piston should be unacceptable condition occurs, the piston should be
replaced. replaced.
Tube Assembly Tube Assembly
Visually inspect the inside bore for scratches and pits. Visually inspect the inside bore for scratches and pits.
There should be no scratches or pits deep enough to There should be no scratches or pits deep enough to
catch the fingernail. Scratches that catch the fingernail but catch the fingernail. Scratches that catch the fingernail but
are less than 0.5 inch long and primarily in the circumfer- are less than 0.5 inch long and primarily in the circumfer-
ential direction are acceptable provided they cannot cut ential direction are acceptable provided they cannot cut
the piston seal. The roughness of the bore should be the piston seal. The roughness of the bore should be
between 10 and 20 between 10 and 20 inches RMS. inches RMS. Significant variati
μ μ
(greater than 8 (greater than 8 inches difference) are unacceptab inches difference) are
μ μ
the event that an unacceptable condition occurs, the tube the event that an unacceptable condition occurs, the tube
assembly should be repaired or re assembly should be repaired or re placed.
5-10 5-10
0.5 inch long and primarily
Chrome should be present
scratches or polishing.
the bore should be
out-of-roundness dness
condition
on the retaining ring groove
unacceptable. Check the con-
Significant variation on
unacceptable. In le. In
placed.
– JLG Lift – – JLG Lift –
Cylinder Assembly Cylinder Assembly
(See Figure 5-3. (See Figure 5-3. ) )
1. 1. Rinse Rinse the in the inside side of th of the tube
allow to drain. A high-pressure rinse followed by a allow to drain. A high-pressure rinse followed by a
wipe with a lint-free rag is preferable. Clean all inter- wipe with a lint-free rag is preferable. Clean all inter-
nal components of any foreign material. nal components of any foreign material.
2. 2. Lubri Lubricate cate the h the head a ead and al nd all sea
prior to installation. Install the seal, wiper, o-ring, prior to installation. Install the seal, wiper, o-ring,
back-up ring, and retraining ring to the cylinder back-up ring, and retraining ring to the cylinder
head. head.
3. 3. Lubri Lubricate cate the the pisto piston an n and a
hydraulic fluid. Install the seal and wear ring to the hydraulic fluid. Install the seal and wear ring to the
piston. piston.
NOTE: NOTE: Re-check that seals are not twisted or pinched and Re-check that seals are not twisted or pinched and
are properly seated. are properly seated.
4. 4. Place Place the ro the rod on a d on a clean t clean table.
ton o-ring seal into the groove on the piston end of ton o-ring seal into the groove on the piston end of
the rod. the rod.
5. 5. Insta Install th ll the head e head foll followed b owed by the
noting the proper orientation of each component. noting the proper orientation of each component.
Torque the piston nut to 100-120 ft. lbs. Torque the piston nut to 100-120 ft. lbs.
6. 6. When When the ro the rod ass d assembly embly is re
the tube, liberally apply an the tube, liberally apply an anti-seize lubricant to the
cylinder head surface which slides into the cylinder cylinder head surface which slides into the cylinder
tube. tube.
7. 7. Next d Next dip th ip the enti e entire rod re rod assemb
and stuff this assembly into the tube. Watch the and stuff this assembly into the tube. Watch the
seals as they pass over the rod port (if visible) seals as they pass over the rod port
sure they are not nicked or cut. sure they are not nicked or cut.
8. 8. Insta Install the h ll the head un ead until th til the retai
groove. groove.
e tube with h with hydrau ydraulic fl lic fluid a uid and nd
l seals wit ls with hy h hydraul draulic fl ic fluid uid
d all c ll compon omponents ents with with
able. Instal Install the l the stati static pis c pis- -
y the pist piston on on onto th to the rod e rod
is ready t ady to be o be insta installed lled into into
anti-seize lubricant to the
assembly in ly into hy to hydraul draulic fl ic fluid uid
(if visible) to be to be
e retaining r ning ring s ing seats in eats in it's it's
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