(2) Install brake return spring.
(2) Visually inspect boom for cracks, breaks,
(3) Install two brake spring rods, springs, and
or excessive wear at boom foot, point, or saddle blocks.
secure with retainers.
Inspect bumper blocks for excessive wear.
(4) Install back plate in brake drum. Make
(3) Repair boom by replacing worn bumper
sure lever (fig. 4-6) is in proper position, then secure
blocks, or welding small cracks. Report large cracks,
back plate to mechanism with flatwasher (fig. 4-9)
bends, or excessive wear beyond scope of organization
lockwasher, and capscrew.
repair to direct support maintenance.
(5) Connect hydraulic hose at coupling nut,
position clevis on lever, then secure with pin.
When shovel boom has been
returned to direct support for repair
4-10. Shovel Boom
or replacement, be sure the returned
equipped with boom point sheaves,
bridle bar, shipper shaft. and crowd
and reverse mechanism.
b. Cleaning, Inspection and Repair.
(1) Clean shovel boom with an approved cleaning
solvent and dry thoroughly.
(4) Perform preventive maintenance checks
Section II. CLAMSHELL, CRANE, AND DRAGLINE FRONT AND ATTACHMENTS
(3) Refer to reeving diagram of front end
attachment in use, disconnect boom hoist, hoist,
The clamshell, crane, and dragline front end
digging, or drag cables at dead end socket, then wind
attachments use a similar boom arrangement, which
cables on drums slowly, while guiding cable end through
consists of the base section, an upper section, and
which may be lengthened by insertion of boom
(4) Use wedges between cribbing at boom
foot and boom; drive them in from each side to take
jib boom attachment that may be installed as required
weight off boom foot pins; remove cotterpins, then
to stabilize the bucket. For dragline
(5) Move crane-shovel basic unit away from
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
according to operation being performed, or length of
boom in use.
from boom point, remove cotterpins and pins, then
This section will cover organizational maintenance as
remove cables from boom spreader.
outlined in Maintenance Allocation Chart.
securing base section to upper section, or boom
4-12. Drum Cable Lagging
The drum lagging for crane, clamshell, and dragline are
removed, or installed, in manner similar to that
When boom (extension) selection 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
(6) Separate the two 10 foot pendant cables