National Crane
Published 5-27-2018 Control # 039-06
6-15
800D
REPAIR
35. Install large extend cable anchor into anchor cutouts in
the doubler plates in the rear of the 2nd by routing the 3/
4 in (19.0 mm) extend cables through the anchor and the
small 3/8 in (9.53 mm) cable over the anchor. Slide
anchor fully into cutout.
36. Install keeper plates and hardware. This keeper plate
retains both the horizontal movement of the extend
anchor and the vertical movement of the telescope
cylinder.
37. Install 2/3/4 section boom assembly into 1st section
boom, use caution when sliding sections together, 3rd
retract cables must maintain their position to prevent
damage, do not let boom rest on cables. Damage will
result.
38. Assemble bottom front wear pads for 1st section and
Teflon plugs.
39. Using appropriate lifting device, lift 2/3/4 section
assembly to allow for wear pad installation in front of 1st.
Install wear pads. Slide sections together within 12 in (30
cm) of full retraction.
40. Install upper spacer to front of 1st section.
41. Install front side wear pads with appropriate shims
between 2nd and 1st sections. If boom has been
disassembled, and no sections have been replaced, use
same shim quantity and location as was previously
used. If locations are in question, refer to shim
calibration section in this book.
42. Push boom together until telescope cylinder butt plate
makes contact with the rear cylinder anchor plates in the
rear of the 1st section. Install spacers, washers and
capscrews, attaching cylinder to 1st section boom. If
cylinder is misaligned with anchor points, cylinder butt
plate can be rotated to achieve proper alignment
(holding valve up, parallel with boom top plate).
43. Assemble new wear pads with the cam plates and install
through the hoist mount end of the boom. Install
capscrews through holes in outer boom sections.
The wear pad on each side at the top/rear of the boom
can be adjusted over a range of 3/16 in (4.8 mm) by
rotating, end for end, the wear pad and plate or the wear
pads and plate independently. This is possible because
the holes in these parts are offset from the center. The
holes are 0.06 in (1.5 mm) off center in the plate and
0.03 in (0.8 mm) off center in the wear pad. Various
combinations of rotation of these parts allow the
adjustment.
44. Install thick hoist attachment bar through hoist mount.
This bar anchors the 3/8 in (9.53 mm) extend cable and
serves as the upper hoist attachment point. Hold this bar
up in its slot with a spacer on each side. This will
facilitate easier assembly.
45. Install the threaded end of the 3/8 in (9.53 mm) extend
cable through hole in center of the hoist attachment bar.
46. Slightly tighten all cables. Cycle boom slowly to assure
proper operation before torquing cables. Refer to the
“Four Section Cable Tensioning” section to properly
torque the cables in the extend system. Cables must be
torqued to proper specifications for proper boom
operation.
47. Install hoist.
FOUR SECTION TOP/BOTTOM PAD
REPLACEMENT ASSEMBLED BOOM
Inspect top and bottom wear pads periodically for signs of
abrasion or excessive wear. Excessive is defined as 3/16 of
an in (4.76 mm) from the original pad thickness, top rear pad
thickness 0.75 in (19 mm), bottom front 1st section 1 in (25
mm), bottom front 2nd and 3rd section 0.44 in (13 mm).
Uneven pad wear of 3/32 in (2 mm) from side to side on the
wear pad would be considered excessive as well. If any of
these conditions exist, the top and bottom pads can be
replaced without complete disassembly of the boom.
Top Rear Pad Replacement
Pad maintenance on the four section can be made easier by
removal of the hoist and or removal of the hoist mounting bar
spanning the end of the 1st section. Additional clearance can
be achieved by loosening the large extend cables and
removing the extend cable anchor located in the 2nd section.
1. Retract boom completely.
2. Remove capscrews through access holes on top rear of
sections.
3. Remove wear pads, shims, and cam plates from the rear
of the boom through open hoist mount end.
4. Note all pad locations and tag accordingly.
5. Inspect pads for wear using previously mentioned
inspection criteria.
6. Assemble new wear pads with the cam plates and install
through the hoist mount end of the boom. Install
capscrews through holes in outer boom sections.
7. The wear pad on each side at the top/rear of the boom
can be adjusted over a range of 3/16 in (4.8 mm) by
rotating, end for end, the wear pad and plate or the wear
pads and plate independently. This is possible because
the holes in these parts are offset from the center. The
holes are0.06 in (1.5 mm) off center in the plate and 0.03
in (0.8 mm) off center in the wear pad. Various
combinations of rotation of these parts allow the
adjustment.
8. Torque retainer capscrews to 110 lb-ft (149 Nm) Failure
to properly torque capscrews will cause loss of preload,
allowing pad cam to rotate and cause excessive side
clearance between sections.
Fo
r
Reference
Only
Summary of Contents for National Crane 800D
Page 1: ...Operator and Service Manual National Crane 800D F o r R e f e r e n c e O n l y ...
Page 4: ...F o r R e f e r e n c e O n l y ...
Page 252: ...SCHEMATICS 800D 2 Published 5 27 2018 Control 039 06 F o r R e f e r e n c e O n l y ...
Page 255: ...F o r R e f e r e n c e O n l y ...
Page 256: ...F o r R e f e r e n c e O n l y ...