JLG G5-18A Service Manual - Manual (Page 23)

3.3 G5-18A/2505
Boom
3.2 BOOM SYSTEM - TWO SECTION
BOOM
3.2.1 Boom System Description
The boom operates via an interchange among the
electrical, hydraulic and mechanical systems. Components
involved include the joystick, tilt cylinder, extend/retract
cylinder, lift/lower cylinder, compensating cylinder,
electronic sensors, various pivots, supporting hardware
and other components.
3.3 BOOM ASSEMBLY MAINTENANCE
The boom assembly consists of the first and second
section booms and supporting hardware.
Note: Before removing the boom or boom section, the
carriage or any other attachment must be removed from
the quick attach.
Before beginning, conduct a visual inspection of the
machine and work area, and review the task about to be
undertaken. Read, understand and follow these
instructions.
During service of the boom, perform the following:
1. Check wear pads. (Refer to Section 3.4.1, “Wear
Pad Inspection.”)
2. Apply grease at all lubrication points (grease fittings).
(Refer to Section 2.6, “Lubrication Schedule.”)
3. Check for proper operation by operating all boom
functions through their full ranges of motion several
times.
Depending on your particular circumstance, the following
procedures explain the removal/installation of individual
boom sections or removal/installation of the complete
boom.
3.3.1 Second Section Boom Removal
1. Remove any attachment from the quick switch
assembly.
2. Be sure there is enough room in front of the machine
to allow the boom sections to be removed. Park the
machine on a hard, level surface, fully retract the
boom, lower the boom, place the transmission
control lever in (N) NEUTRAL, engage the park
brake and shut the engine OFF.
3. Place an Do Not Operate Tag on both the ignition
key switch and the steering wheel, stating that the
machine should not be operated.
4. Remove the battery negative (-) cable from the
battery negative (-) terminal.
5. Open the engine cover. Allow the system fluids to
cool.
6. Remove the quick switch assembly. Refer to Section
3.5.5, “Quick Attach Removal.”
7. Label and disconnect the tilt hoses and (if equipped)
auxiliary hydraulic hoses attached to the machine at
the boom head. Plug and cap the hose ends to
prevent dirt and debris from entering the hydraulic
system.
8. Label and disconnect the extend/retract hydraulic
tubes on the extend/retract cylinder at the rear of the
boom.
9. Tag or identify each hose to the corresponding fitting
it was removed from.
10. Remove the top and side wear pads from the rear of
the second boom section.
Note: Tag each pad, backing plate, shim and bolts from
each location.
11. Remove the lock bolt and nut (1) from the rear of the
extend/retract cylinder.
12. Remove the extend/retract cylinder mounting pin (2).
13. Support the front of the boom by placing a sling
behind the boom head. Pull the second boom
section out of the first boom section approximately
6 in to 8 in (15 cm to 20 cm).
14. Pull the tilt hoses and (if equipped) auxiliary
hydraulic hoses through the rear of the boom.
15. Remove the top, side and bottom wear pads from
the front of the first boom section.
Note: Tag each pad, backing plate, shim and bolts from
each location.
MY1960
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