National Crane 01-22-2019 Control # 051-08 4-5
1300A BOOM MAINTENANCE
BOOM DISASSEMBLY
The front of the boom is the sheave case end and the rear of
the boom is the hoist mount end. Left and right are viewed
from the rear to the front.
NOTE: The hoist can be removed to facilitate disassembly,
but it is not required.
2
nd
, 3
rd
, 4
th
Boom Section Removal
To remove the 2
nd
, 3
rd
, 4
th
sections from the 1
st
section as an
assembly, use the following procedure:
1. Remove the left and right upper wear pads in the rear
between the 1
st
and 2
nd
boom sections (Figure 4-6).
NOTE: The lower wear pads are not removed at this time.
They are left in to aid in protecting the extend
cables during removal of the 2
nd
, 3
rd
, 4
th
boom
sections.
2. Loosen and remove the two capscrews, lockwashers
and spacers that anchor the extend cylinder rod butt
plate to the rear of the 1
st
section.
3. Attach a suitable lifting device to the 2
nd
, 3
rd
, 4
th
boom
section assemblies.
4. Slide the 2
nd
, 3
rd
, 4
th
boom section assemblies out
about 2 feet.
5. Tag and remove the top and side wear pads, shims, and
wear plates. Leave the bottom wear pads in.
6. With the 2
nd
, 3
rd
, 4
th
boom section assembly supported,
slide the assembly out of the 1
st
section until the
assembly is just ready to drop out of 1st section.
Relocate the sling on the 2
nd
, 3
rd
, 4
th
boom assembly so
that the assembly is balanced as it slides out of the 1
st
section.
NOTE: Keep the retract cables tensioned slightly by hand
as the assembly is pulled out of the 1
st
section to
prevent damage to cable assemblies.
7. Loosen and remove the two capscrews and
lockwashers securing the spacer bar to the inside top
front of the 1
st
section. Remove the spacer bar.
8. Loosen and remove four capscrews securing wear pads
to the bottom of the 1
st
section.
9. Raise the 2
nd
, 3
rd
, 4
th
boom assembly inside the 1
st
section to allow for front bottom pad removal. Tag and
remove the bottom wear pads.
10. After the wear pads have been removed, slide the 2
nd
,
3
rd
, 4
th
assembly out of the 1
st
section and place on a
suitable horizontal surface. Take care not to pinch or
crush the retract cables while lifting or supporting
assembly.
Disassembly of 2
nd
, 3
rd
, 4
th
Boom Sections
1. Loosen and remove the four capscrews securing the two
top rear wear pads on the 2
nd
section. Tag and remove
the wear pads, shims, and plates.
NOTE: Keep all parts for each wear pad together so that
the correct shims are in place for reassembly.
2. Loosen and remove the four capscrews securing the
rear bottom wear pads on the 2
nd
section.
NOTE: Removal of these pads allow the retract cables to
uncoil off the retract sheaves.
3. Place the retract cable ends in a location to minimize the
possibility of damage.
4. Loosen and remove the six capscrews securing the
retract sheave pin and retract sheaves to the 2
nd
section. Remove the sheaves and pins.
DANGER
Do not, under any circumstances, work at an elevated
height without using proper fall protection as required by
local, state or federal regulations.
FIGURE 4-6
Upper Wear Pad
Extend Cylinder
Butt Plate Nuts
Proportion
Cable
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