(2) Visually inspect boom for cracks, breaks,
(2) Install brake return spring.
or excessive wear at boom foot, point, or saddle blocks.
(3) Install two brake spring rods, springs, and
Inspect bumper blocks for excessive wear.
secure with retainers.
(3) Repair boom by replacing worn bumper
(4) Install back plate in brake drum. Make
blocks, or welding small cracks. Report large cracks,
sure lever (fig. 4-6) is in proper position, then secure
bends, or excessive wear beyond scope of organization
back plate to mechanism with flatwasher (fig. 4-9)
repair to direct support maintenance.
lockwasher, and capscrew.
(5) Connect hydraulic hose at coupling nut,
When shovel boom has been
position clevis on lever, then secure pin.
returned to direct support for repair
or replacement, be sure the returned
4-10. Shovel Boom
equipped with boom point sheaves,
bridle bar, shipper shaft, and crowd
and reverse mechanism.
(1) Install shovel boom (para 42).
b. Cleaning, Inspection and Repair.
(4) Perform preventive maintenance checks
(1) Clean shovel boom with an approved
cleaning solvent and dry thoroughly.
Section II. CLAMSHELL, CRANE, AND DRAGLINE FRONT END ATTACHMENTS
digging, or drag cables at dead end socket, then wind
cables on drums slowly, while guiding cable end through
The clamshell, crane, and dragline front end
attachments use a similar boom arrangement, which
consists of the base section, an upper section, and
(4) Use wedges between cribbing at boom
which may be lengthened by insertion of boom
foot and boom; drive them in from each side to take
weight off boom foot pins; remove cotterpins, then
jib boom attachment that may be installed as required
(5) Move crane-shovel basic unit away from
to stabilize the bucket. For dragline
operation, a fairlead and sheaves (para 4-16) is installed
at revolving frame. All of these attachments use the
b. Disassembly and Reassembly.
pin, then remove boom backstop. Disassemble boom
backstop (para 4-20).
(2) Remove radius (boom angle) indicator
according to operation being performed, or length of
boom in use. This section will cover organizational
maintenance as outlined in Maintenance Allocation
from boom point, remove cotterpins and pins, then
remove cables from boom spreader.
412. Drum Cable Lagging
securing base section to upper section, or boom
The drum lagging for crane, clamshell, and dragline are
removed or installed, in manner similar to that described
in paragraph 3124.
When boom (extension) section is
installed in boom, proceed as in step
(1) Disconnect boom backstop from gantry
securing boom (extension) section to upper section,
then remove boom (extension) section from upper
(3) Refer to reeving diagram of front end
attachment in use, disconnect boom hoist, hoist,