National Crane 1-21-2019 Control # 104-07 4-13
1400A SERVICE MANUAL BOOM MAINTENANCE
• Install the cable guide and wear pad to the top of the
2
ND
section.
40. Slide the 3
RD
-4
TH
-5
TH
section and cylinder assembly into
the 2
ND
section until the extend cylinder collar bottoms
out in its anchor pocket in the rear of the 2
ND
section or
the 3
RD
section side plates bottom out on the doubler
plates on the rear of the 2
ND
section. Use caution as the
4
TH
section retract cable threaded ends get close to the
grooves in the lower front pad plate and adjust as
necessary to allow proper placement.
41. A cylinder length adjustment may be necessary to
properly position the cylinder collar in the anchor pocket
with the 3
RD
section side plates. The collar bottoms out
on the doublers in the rear of the 2
ND
section. A hydraulic
power source may have to be utilized to adjust the
cylinder length.
• Secure the extend cylinder collar to the cylinder
mounting channels in the rear of the 2nd section
boom with appropriate hardware.
• A scribe mark on the 3
RD
section at full retraction
aids in cable tensioning for proper boom sequence
later.
42. Install the top rear wear pads with the cam plates in the
top of the 3
RD
section. See step #12 for pad installation
detail.
43. Install the 3
RD
section retract cable button ends into the
anchors points in the rear of the 3rd section. Install
keeper plates and capscrews. Assemble with
loctite 243.
44. Install the 2
ND
section retract sheaves and pins in the 2
ND
section boom. Use the proper hardware and Loctite 243.
• Reeve the 3
RD
section retract cables, anchored to
3
RD
section, over sheaves attached to 2
ND
section.
• Install the upper keeper capscrew and lower rear
pad. The pad serves as a cable keeper, lower pad,
and side pad for the rear of the section.
45. Pull threaded ends of 3
RD
section retract cables, now
under the 2
ND
section, towards the front of the boom.
46. Suspend the assembled boom sections.
• Rotate the rod assembly to achieve proper
orientation.
• Place the retract cables so as to avoid damage.
• Slide the assembled boom sections into the 1
ST
section about 90 cm (36 inches).
• Keep the boom assembly suspended to avoid
damage to the retract cable.
47. Install the bottom wear pads on 2
ND
section pad plate.
• Raise the 2
ND
-3
RD
-4
TH
-5
TH
section and cylinder
assembly high enough in 1
ST
section to allow the
plate with pads to slide between the sections.
• Place the retract cables in the grooves in the bottom
pad plate. As the boom sections slide together, the
retract cables are pulled through the grooves. Use
appropriate hardware and fasten the pad plate to
the bottom plate of the 1
ST
section.
48. Install a nut on the threaded ends of the 3
RD
section
retract cables to keep the cable ends from pulling
through the anchor as the sections are pushed together.
49. Push the 2
ND
-3
RD
-4
TH
-5
TH
section and cylinder assembly
inside the 1
ST
section, until it is within 90 cm (36 inches)
of full insertion.
50. Install the side wear pads with the appropriate shims on
the front inside of the 1
ST
section boom.
• Install upper spacer bar with appropriate hardware
to the inside top of the 1
ST
.
• Shim according to calibration instructions, or as
pads were originally removed and tagged.
51. Slide the 2
ND
-3
RD
-4
TH
-5
TH
section and cylinder assembly
into the 1
ST
section until the extend cylinder butt plate
contacts the back plate of the hoist mount.
• Use caution as the holding valve nears the hoist
mount back plate. The holding valve to back plate
clearance requires the butt plate to be level with the
holding valve down.
• Use caution as the 3
RD
section retract cable
threaded ends get close to the grooves in the lower
front pad plate. Adjust as necessary to allow proper
placement.
52. Install the proper hardware to secure the extend cylinder
butt plate to the 1
ST
section hoist mount.
53. Assemble top rear wear pads with the cam plates to the
top of the 2
ND
section. See step #12 for pad installation
detail.
54. Install the cable guides, angle pendulum, hoist and anti-
two block system. See the anti-two block system
description and installation instructions.
Boom Straightness
Extended boom straightness is critical in proper boom
operation. The extended boom straightness required is a
deviation of 13 mm (0.50 inch) or less from the centerline of
the boom. A string line from the center of the hoist to the
middle of the sheave case on the last section provides a
centerline. The top rear pads should be adjusted accordingly
to provide proper clearances to achieve a straight extended
boom.
Fo
r
Reference
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