SECTION 5 - HYDRAULICS
5-20
– JLG Lift –
3121290
6.
Using suitable protection, clamp cylinder rod in a vise or
similar holding fixture as close to piston as possible.
7.
Loosen and remove cap screws attaching tapered bush-
ing to piston.
8.
Insert cap screws in threaded holes in outer piece of
tapered bushing. Progressively tighten cap screws until
bushing is loose on piston.
9.
Remove bushing from piston.
Figure 5-36. Tapered Bushing Removal
10.
Screw piston counter-clockwise by hand and remove
piston from cylinder rod.
11.
Remove and discard piston seals and lock rings.
12.
Remove rod from holding fixture. Remove cylinder head
and ring washer. Discard O-rings, back-up rings, rod
seals, and wiper seals.
CLEANING AND INSPECTION
1.
Clean all parts thoroughly in an approved cleaning sol-
vent.
2.
Inspect cylinder rod for scoring, tapering, ovality, or
other damage. Dress rod with Scotch Brite or equivalent
as needed. Replace rod if necessary.
3.
Inspect threaded portion of rod for excessive damage.
Dress threads as necessary.
4.
Inspect inner surface of cylinder barrel tube for scoring
or other damage. Check inside diameter for tapering or
ovality. Replace if necessary.
5.
Inspect threaded portion of barrel for damage. Dress
threads as necessary.
6.
Inspect piston surface for damage, scoring, and distor-
tion. Dress piston surface or replace piston as needed.
7.
Inspect threaded portion of piston for damage. Dress
threads as necessary.
8.
Inspect seal and O-ring grooves in piston for burrs and
sharp edges. Dress surfaces as necessary.
9.
Inspect cylinder head inside diameter for scoring or
other damage, and for ovality and tapering. Replace as
necessary.
10.
Inspect threaded portion of head for damage. Dress
threads as necessary.
11.
Inspect seal and O-ring grooves in head for burrs and
sharp edges. Dress surfaces as necessary.
12.
Inspect cylinder head outside diameter for scoring or
other damage, ovality, and tapering. Replace as needed.
13.
Inspect rod and barrel bearings for excessive wear or
damage. Replace as necessary.
a. Thoroughly clean hole, (steel bushing) of burrs, dirt
etc. to facilitate bearing installation.
b. Inspect steel bushing for wear or other damage. If
steel bushing is worn or damaged, rod/barrel must
be replaced.
c. Lubricate inside of steel bushing with WD40 before
installing composite bushings.
d. Using a correct size arbor, press bearing into steel
bushing.
NOTE:
Lubrication is not required with nickel plated pins and
bearings. Install pin in composite bushing dry.
Figure 5-37. Composite Bushing Installation
14.
Inspect oil ports for blockage or presence of dirt or other
foreign material. Repair as needed.
15.
Inspect piston rings for cracks or other damage. Replace
as needed.
Summary of Contents for 450A II Series
Page 46: ...SECTION 3 CHASSIS TURNTABLE 3 6 JLG Lift 3121290 Figure 3 4 Drive Hub 4WD Front Only ...
Page 79: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 39 Figure 3 32 Swing Bearing Drive ...
Page 101: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 61 Figure 3 42 Auxiliary Pump ...
Page 113: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 73 Figure 3 53 EMR2 Fault Codes Sheet 1 of 5 ...
Page 114: ...SECTION 3 CHASSIS TURNTABLE 3 74 JLG Lift 3121290 Figure 3 54 EMR2 Fault Codes Sheet 2 of 5 ...
Page 115: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 75 Figure 3 55 EMR2 Fault Codes Sheet 3 of 5 ...
Page 116: ...SECTION 3 CHASSIS TURNTABLE 3 76 JLG Lift 3121290 Figure 3 56 EMR2 Fault Codes Sheet 4 of 5 ...
Page 117: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 77 Figure 3 57 EMR2 Fault Codes Sheet 5 of 5 ...
Page 159: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 119 ...
Page 161: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 121 ...
Page 163: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 123 ...
Page 165: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 125 ...
Page 173: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 133 Sensor Transducer Type ...
Page 177: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 137 Sensor Transducer Type ...
Page 179: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 139 ...
Page 181: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 141 ...
Page 183: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 143 ...
Page 185: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 145 ...
Page 187: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 147 ...
Page 203: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 163 ...
Page 207: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 167 ...
Page 217: ...SECTION 4 BOOM PLATFORM 3121290 JLG Lift 4 5 Figure 4 2 Boom Limit Switches ...
Page 310: ...SECTION 5 HYDRAULICS 5 70 JLG Lift 3121290 NOTES ...
Page 312: ...SECTION 6 JLG CONTROL SYSTEM 6 2 JLG Lift 3121290 Figure 6 2 Controller Block Diagram 0 ...
Page 370: ...SECTION 6 JLG CONTROL SYSTEM 6 60 JLG Lift 3121290 NOTES ...
Page 394: ...SECTION 7 BASIC ELECTRICAL INFORMATION SCHEMATICS 7 24 JLG Lift 3121290 NOTES ...
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