SECTION 5 - HYDRAULICS
5-6
– JLG Lift –
3121290
8.
Remove cap screws from tapered bushing.
9.
Insert cap screw in threaded holes in outer piece of
tapered bushing. Progressively tighten cap screw(s) until
bushing is loose on piston.
10.
Remove bushing from piston.
Figure 5-6. Tapered Bushing Removal
11.
Screw piston counter-clockwise and remove from rod.
12.
Remove and discard piston O-rings, seal rings, and
backup rings.
13.
Remove piston spacer and two wear rings from rod.
14.
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 in approved cleaning solvent.
2.
Inspect cylinder rod for scoring, tapering, ovality, or
other damage. If necessary, dress rod with Scotch Brite
or equivalent. Replace rod if necessary.
3.
Inspect threaded portion of rod for excessive damage.
Dress threads as necessary.
4.
Inspect inner surface of cylinder barrel 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 and scoring and for
distortion. Dress piston surface or replace piston as nec-
essary.
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. 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 signs of 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 the steel bushing with WD40
prior to bearing installation.
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 5-7. Composite Bushing Installation
14.
Inspect travel limiting collar or spacer for burrs and
sharp edges. Dress inside diameter as needed. Inspect
port block fittings and holding valves. Replace as
needed. Torque holding valves to 50-55 ft-lb (68-75 Nm).
15.
Inspect oil ports for blockage or presence of dirt or other
foreign material. Repair as necessary.
16.
Inspect piston rings for cracks or other damage. Replace
as necessary.
Summary of Contents for 450A II Series
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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 ...
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Page 115: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 75 Figure 3 55 EMR2 Fault Codes Sheet 3 of 5 ...
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Page 117: ...SECTION 3 CHASSIS TURNTABLE 3121290 JLG Lift 3 77 Figure 3 57 EMR2 Fault Codes Sheet 5 of 5 ...
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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 ...
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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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