SkyTrak 8042 Service Manual - Manual (Page 53)

3-15 6036, 6042, 8042, 10042, 10054
Boom
3.5 BOOM SYSTEM - FOUR SECTION
(10054)
3.5.1 Boom System Operation
The four section boom consists of the fourth, third,
second and first boom assemblies with double
intermediate boom extend chains, a single inner boom
extend chain, a single inner boom retract chain and a
single intermediate boom retract chain.
As the Extend/Retract hydraulic cylinder, which is
anchored at the front of the second boom section, and the
rear of the first boom section begins to extend, it forces
the second boom section out of the first boom section.
The fourth, third, second and first boom sections are
connected by extend and retract chains. These chains
are routed around sheaves on the third and second boom
sections. As the second and third boom sections are
forced out, the extend chain pulls the fourth boom section
out of the third.
As hydraulic pressure is applied to the retract port on the
Extend/Retract cylinder, the third boom section is pulled
back into the fourth boom section, and the retract chain
pulls the third and fourth boom sections back into the
second boom section.
This mechanical linkage formed by the chains and
supporting hardware, extends and retracts the second,
third and fourth boom sections at the same rate.
The first boom section does not extend or retract, but lifts
and lowers via action of the Lift/Lower cylinders.
3.6 BOOM ASSEMBLY MAINTENANCE
These instructions must be completed in sequence. The
fourth boom section must be removed before removing
the third boom section. The third boom section must be
removed before removing the second boom section.The
fourth, third and second boom section must be removed
at one time before removing the first boom section.
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.
3.6.1 Fourth Boom Section Removal
1. Remove any attachment from the quick attach
assembly. Refer to Section 3.8.1, “Disconnecting
from an Attachment.”
Note: If replacing the fourth section boom, remove the
quick attach from the fourth section. Refer to Section
3.8.3, “Quick Attach Removal.”
2. Park the machine on a hard, level surface, level the
machine, 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 a Do Not Operate Tag on both the ignition key
switch and the steering wheel, stating that the
machine should not be operated.
4. Open the rear door. Allow the system fluids to cool.
5. Move the Attachment Tilt joystick in both directions
to relieve any trapped pressure in the Attachment
Tilt system. If the machine is equipped with Auxiliary
controls, move the Auxiliary hydraulic joystick in both
directions to relieve any trapped pressure in the
Auxiliary hydraulic system.
6. Label, disconnect and cap the hoses attached to the
Attachment Tilt cylinder. Cap all fittings to keep dirt
and debris from entering the hydraulic system.
7. If the machine is equipped with Auxiliary hydraulics,
label, cap and remove the hoses from the bulkhead
fittings.
If replacing the fourth boom section with a new boom
section: Remove the female coupler, male nipple
and bulkhead fittings from the bulkhead plate inside
the boom head.
8. Remove the rear cover from the boom.
9. At the front of the first boom section, label and
remove the hydraulic hoses from the bottom tube
assemblies at the mounting plate (16). Cap the hose
ends.
WARNING
NEVER weld or drill the boom unless approved in
writing by the manufacturer. The structural integrity of
the boom will be impaired if subjected to any repair
involving welding or drilling.
MH1451
16