SECTION 5 - HYDRAULICS
3121259
– JLG Lift –
5-3
5.2
HYDRAULIC CYLINDERS
Holding (counterbalance) valves are used in the Lift, Level, Jib,
Telescope, and Axle Lockout circuits to prevent retraction of
the cylinder rod should a hydraulic line rupture or a leak
develop between the cylinder and its’ related holding valve.
NOTE:
The steer cylinder weighs approximately 37.2 lbs (16.9 kg).
NOTE:
The tower lift cylinder weighs approximately 76 lbs (34.5
kg).
NOTE:
The upper lift cylinder weighs approximately 97 lbs (44 kg).
NOTE:
The master cylinder weighs approximately 35.3 lbs (16 kg).
NOTE:
The level cylinder weighs approximately 37.4 lbs (17 kg).
NOTE:
The jib lift cylinder weighs approximately 55 lbs (25 kg).
NOTE:
The telescope cylinder weighs approximately 52.7 lbs (23.9
kg).
NOTE:
The axle oscillation lockout cylinder weighs approximately
26.2 lbs(11.9 kg).
Disassembly and Assembly Instructions
1.
Make sure the work area is large enough for the entire
cylinder and clean and free of dirt. Ensure the cylinder
can be secured firmly in place during disassembly.
2.
Prepare all the necessary tools and replacement parts.
Refer to Table 5-2, Required Tools.
General Information
1.
Clean any burrs or contamination from the surface of
the cylinder before disassembly.
2.
Handle every part with care. Each part is precision made
and hitting parts together or letting them fall could
damage the machined surfaces.
3.
Do not twist or strike parts to get them apart. This will
damage the part and/or threads, resulting in leakage
and poor function.
4.
Do not let the cylinder in a disassembled condition for a
long period of time. It only takes a short period of time
for the parts to rust.
Standard of Maintenance
Parts and seals should be replaced according to the conditions
as follows.
1.
Bushings - 1/4 of the bushing is worn off.
2.
Seal and Slide Ring - Replace during disassembly.
3.
Pin Bushing - When it is worn down.
4.
Rod - Bent or warped more than 0.5mm/1m.
Inspection After Assembly
Table 5-1. Inspection After Assembly
Operation Inspection Without
Load
There is no problem when fully extended 5 times without load
Dimension
Check the retracted length and stroke
Inspection of the Surface
When each of the cylinders are pressurized with test pressure on the piston end, it should not be loose and have no change in pressure or external
leakage
Inspection of external leakage
Check the oil leakage at the rod area. Refer to Figure 5-1., Acceptable Oil Leakage on Cylinder Rod.
Inspection of internal leakage
Leakage Unit: ml/ 10 minutes
Bore (mm)
Leakage (ml)
Bore (mm)
Leakage (ml)
Bore (mm)
Leakage (ml)
Remark
32
0.4
100
4
160
10
40
0.6
125
5.6
180
12.6
50
1
140
6
200
15.6
63
1.6
220
20
80
2.3
250
22
Summary of Contents for 340AJ
Page 1: ...Service and Maintenance Manual Model 340AJ P N 3121259 June 27 2017...
Page 2: ......
Page 10: ...vi JLG Lift 3121259 TABLE OF CONTENTS SECTION NO TITLE PAGE NO Thispageleftblankintentionally...
Page 15: ...3121259 JLG Lift xi LIST OF FIGURES FIGURE NO TITLE PAGE NO Thispageleftblankintentionally...
Page 18: ...xiv JLG Lift 3121259 LIST OF TABLES TABLE NO TITLE PAGE NO Thispageleftblankintentionally...
Page 42: ...SECTION 2 GENERAL 2 12 JLG Lift 3121259 NOTES...
Page 69: ...SECTION 3 CHASSIS TURNTABLE 3121259 JLG Lift 3 27 Figure 3 24 Bearing Pressing Tool...
Page 71: ...SECTION 3 CHASSIS TURNTABLE 3121259 JLG Lift 3 29 Figure 3 27 Bearing Nut Wrench...
Page 134: ...SECTION 3 CHASSIS TURNTABLE 3 92 JLG Lift 3121259 NOTES...
Page 157: ...SECTION 4 BOOM PLATFORM 3121259 JLG Lift 4 23 Figure 4 8 Rotator Counterbalance Valve...
Page 218: ...SECTION 5 HYDRAULICS 5 58 JLG Lift 3121259 Figure 5 32 Fasteners and Plugs Sheet 1 of 2...
Page 219: ...SECTION 5 HYDRAULICS 3121259 JLG Lift 5 59 Figure 5 33 Fasteners and Plugs Sheet 2 of 2...
Page 236: ...SECTION 5 HYDRAULICS 5 76 JLG Lift 3121259 Figure 5 39 Gear Pump Cutaway...
Page 246: ...SECTION 5 HYDRAULICS 5 86 JLG Lift 3121259 Figure 5 40 Oil Sampling Port...
Page 256: ...SECTION 6 JLG CONTROL SYSTEM 6 10 JLG Lift 3121259 Figure 6 3 Ground Module Sheet 1 of 4...
Page 273: ...SECTION 6 JLG CONTROL SYSTEM 3121259 JLG Lift 6 27 Figure 6 16 Analyzer Machine Setup Menu...
Page 274: ...SECTION 6 JLG CONTROL SYSTEM 6 28 JLG Lift 3121259 Figure 6 17 Analyzer Calibrations Menu...
Page 336: ...SECTION 6 JLG CONTROL SYSTEM 6 90 JLG Lift 3121259 NOTES...
Page 368: ...SECTION 7 BASIC ELECTRICAL INFORMATION SCHEMATICS 7 32 JLG Lift 3121259 NOTES...
Page 369: ......
