JLG 1230ES, Руководство по обслуживанию и ремонту

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SECTION 4 - BASE COMPONENTS
4-8 – JLG Lift – 3121222
Hydraulic Cylinder Component Inspection
Cylinder Rod
There should be no scratches or pits deep enough to catch
the fingernail. Pits that go to the base metal are unaccept-
able. Scratches that catch the fingernail but are not to the
base metal, less than 0.5 inch long and primarily in the cir-
cumferential direction are acceptable provided they can-
not cut the rod seal. Chrome should be present over the
entire surface of the rod and the lack thereof is unaccept-
able. In the event that an unacceptable condition occurs,
the rod should be repaired or replaced.
Cylinder Head (Gland)
Visually inspect the inside bore for scratches or polishing.
Deep scratches are unacceptable. Polishing indicates
uneven loading and when this occurs, the bore should be
checked for out-of-roundness. If out-of-roundness exceed
0.007", this is unacceptable. Check the condition of the
dynamic seals (wiper, rod seals) looking particularly for
metallic particles embedded in the seal surface. It is nor-
mal to cut the static seal on the retaining ring groove
upon disassembly. Remove the rod seal, static o-ring and
backup and rod wiper. Damage to the seal grooves, partic-
ularly on the sealing surfaces, is unacceptable. In the event
that an unacceptable condition occurs, the head should
be replaced.
Piston
Visually inspect the outside surface for scratches or polish-
ing. Deep scratches are unacceptable. Polishing indicates
uneven loading and when this occurs, the diameter
should be checked for out-of-roundness. If out-of-round-
ness exceeds 0.007", this is unacceptable. Check the condi-
tion of the dynamic seals and bearings looking
particularly for metallic particles embedded in the bearing
and in the piston seal surface. Remove the seals and bear-
ings. Damage to the seal grooves, particularly on the seal-
ing surfaces, is unacceptable. In the event that an
unacceptable condition occurs, the piston should be
replaced.
Tube Assembly
Visually inspect the inside bore for scratches and pits.
There should be no scratches or pits deep enough to catch
the fingernail. Scratches that catch the fingernail but are
less than 0.5 inch long and primarily in the circumferential
direction are acceptable provided they cannot cut the pis-
ton seal. The roughness of the bore should be between 10
and 20 μ inches RMS. Significant variation (greater than 8
μ inches difference) are unacceptable. In the event that an
unacceptable condition occurs, the tube assembly should
be repaired or replaced.
Steer Cylinder - Assembly
NOTE:
Prior to cylinder assembly, ensure the proper JLG
seal kits are used, see the JLG Parts Manual.
Apply a light film of the hydraulic oil to be used for operation to
all components to be assembled, except the threaded areas where
loctite is to be applied.
1. Load the seals, o’rings, and backing ring onto the
cylinder head (gland).
2. Lubricate the cylinder rod surface with clean
hydraulic oil, then slide the cylinder head (gland)
assembly onto the rod.
3. Check that the threads on the cylinder rod and
inside the piston are clean and free of any
hydraulic oil.
4. Apply Loctite #242 to the threads of the cylinder
rod and thread the piston onto the end of the
cylinder rod, tighten piston with the proper
spanner wrench and torque the piston to 260Nm
(55 ft. lb.).
Piston Installation
1. Threaded End of Rod (a)
2. Piston (b)
3. Cylinder Head (Gland)
4. Piston Set Screw (c)
5. Piston (Kban) Seal
NOTE:
(a) Apply Loctite #242 on final assembly
(b) Torque piston to 260Nm (55 ft. lb.)
(c) Apply Loctite #222 and torque to 20Nm (5 ft.
lb.)