SECTION 4 – BOOM
4-14
USTC
January 15, 2001
•
Inspect boom pivot pin for wear, scoring or other
damage and for tapering or ovality. replace pin as
necessary.
•
Inspect upper lift cylinder attach pin for tapering,
ovality, scoring, wear or other damage. Ensure
pin surfaces are protected prior to installation.
Replace pin as necessary.
•
Inspect extend cable anchor plates for wear of
other damage. Replace anchor plates as neces-
sary.
•
Inspect inner diameter of boom pivot bushing for
scoring, distortion, wear or other damage. Re-
place bushing as necessary.
•
Inspect all wear pads for excessive wear or
damage. Replace wear pads when worn to within
1/16 in. of insert.
•
Inspect extend and retract cables for stretching,
distortion or other damage. Replace components
as necessary.
•
Inspect all threaded components for damage,
including stretching, thread deformation or twist-
ing. Replace as necessary.
•
Inspect structural units of boom assembly for
bending, cracking, separation of welds or other
damage. Replace boom sections as necessary.
Boom Assembly
The boom assembly procedure covers installation of
a complete new boom, including new wear pads.
Some steps may not be necessary if reusing existing
parts. Always shim wear pads correctly after assem-
bly.
WARNING: NEVER ALLOW SECTIONS
TO REST ON CABLES WHILE ASSEMBLING.
CABLES MAY BE DAMAGED.
1. Measure inside dimension of outer-mid, inner-
mid and base sections. Install wear pads and
shims to side, top and outside of each section
allowing 1/16 in. clearance between inner and
outer dimensions of each section.
Note: Mark both ends of the cables to ensure that
they do not cross inside of the boom.
2. Place sheaves on pins inside outer-mid section.
Attach adjuster end of fly section retract cables
to fly section using clamps at the pedestal end.
Use mechanic’s wire to hold middle of cable in
approximate location of sheaves inside outer-
mid section. Lay bullet end of extend cables in
approximate position at pedestal end.
3. Attach ramp to fly section. Using mechanic’s
wire, hold ramp up as high as possible. Pull
cable ends, top and bottom, in towards center of
fly section to prevent catching inner sheaves.
4. Insert fly section into outer-mid section. Be sure
ramp stays in position. Remove mechanic's wire
holding middle of extend cable before cable is
completely inserted. Slide in until approximately
12 in. of retract remains.
5. At the nose end, insert the top wear pad and two
bottom wear pads and shims. Shim as necessary
to provide 1/16 in. clearance. Be sure to orient
wear pads toward outside edge of section.
6. Insert four side wear pads loosely to inside of
outer-mid section. Shims will be added after
boom is assembled.
7. Attach cable anchor blocks on top of extend
cables at pedestal end of fly section. (Do not use
lock washers on block bolts due to clearance.)
Shim as necessary to center the fly section
within the outer-mid section.
8. Install lower retract cable sheaves in outer-mid
section. Do not install cotter pins in sheave pins.
9. Loosely attach hose clamp to bullet end of
cable. Lay bullet end of retract cable in cable
anchor block. Slide hose clamp against anchor
block and tighten to prevent cable from coming
out of seat.
10. Reeve cable around sheaves and under fly sec-
tion. Be sure to go over cross bar underneath
sheaves. Stretch cable out for the length of
section and attach cable mount to adjuster end
of cables. Leave cable lay under fly section.
11. Insert fly/outer-mid assembly into inner-mid
section. After side wear pads are inside inner-
mid section, locate bottom wear pads under
assembly to protect retract cables. With ap-
