National Crane 600H, Service Manual

Page: 85 / 232

NATIONAL CRANE
08-19-2022 Control # 092-13
4-11
600H SERVICE MANUAL BOOM
4
FOUR SECTION BOOM MAINTENANCE
Internal Cable Sheave Lubrication
Special Tools: Nozzle or needle grease gun fitting.
The lubrication points on the sheaves are not equipped with
grease fittings (zerks), therefore a 0.25 in (6.35 mm)
diameter nozzle grease gun tip will be required. Contact the
National Crane Care to obtain this nozzle tip (NCC Part No.
955047), or numerous variations of the nozzle tip can be
purchased at local hardware or auto parts retail outlets.
NOTE: Observation through the sheave case for the
extend sheaves and the hoist mount for retract
sheaves will visually determine the amount of
grease necessary for proper lubrication. A slight
amount of grease extrusion around the pin joint is
adequate for proper lubrication.
Lubrication of the extend cable sheaves located on the boom
tip end of the extend cylinder, and the retract cable sheaves
located on the inside rear of the 2
nd
and 3
rd
section and the
extend cable sheave attached to the bottom of the top plate
of the second section at the sheave case end of the boom,
are accomplished as follows:
1. Extend boom until grease access hole becomes visible
in side plate of 2
nd
section as it extends out of 1
st
section.
2. Visually check alignment between the 2
nd
section
access hole and the access holes in 3
rd
and 4
th
section.
When these holes become aligned, the end of the
extend cable sheave pin will be visible and accessible
for lubrication.
3. This boom extended position will coincide with proper
alignment of the access holes in the rear of the 1
st
section for lubrication of the retract sheaves attached to
the rear of the 2
nd
and 3
rd
section.
4. The extend cable sheave located on the bottom of the
top plate of the 2
nd
section at the sheave case end of the
boom can be accessed at any boom length for
lubrication.
Four Section Cable Tensioning
After boom reassembly or from time to time if interior
proportioning cables appear loose, cable tensioning may be
required. Tensioning must be done with the boom horizontal.
For more information, see “Cable Tensioning” on page 4-16.
Four Section Boom Service
1. Extend and set machine outriggers. Boom must be
completely retracted and stowed in the boom rest.
2. If equipped, remove swing around jib according to
procedures outlined in the Operators Handbook.
3. Remove hook block or downhaul weight, wind up rope
on hoist drum and stow wedge socket on pegs provided
on 1
st
section. Shutdown truck engine.
4. Attach a lifting device to rod end of lift cylinder, remove
boom lift cylinder pin keeper and pin from bottom of the
1
st
section boom. Lower lift cylinder to a suitable
support.
5. Tag and disconnect extend cylinder lines and hoist
hydraulic lines. Cap all open lines and ports.
6. Attach a lifting device to provide even weight distribution
and raise the boom until weight is removed from the
boom pivot pin. Remove boom pivot pin keeper and
boom pivot pin. Lift boom free of turret.
FOUR SECTION BOOM DISASSEMBLY
The 600H boom can be disassembled by using two different
methods. Alternative #1 disassembles the boom in the
conventional manner. Alternative #2 removes the extend
cylinder from the rear of the boom, after removal of the hoist.
This feature facilitates cylinder service with out complete
boom teardown.
For reference, the front of the boom refers to the sheave
case end, the rear of the boom is the hoist mount end. Left
and right are viewed from front to rear.
If the boom is to be unpinned from the turret of the crane
structure, please refer to the Boom Removal Procedure
section in this book. If the required service procedure is to be
performed on the boom while still pinned to the turret, please
follow these directions.
.
1. Extend and set the outriggers.
2. Fully retract the boom and place in a horizontal position.
3. Hoist removal optional.
WARNING
Do not, under any circumstances, work at an elevated
height without using proper fall protection as required by
local, state or federal regulations
Boom Length Boom Weight CG from pivot point
90’ 7210 lb (3270 kg) 145” (3.68 m)
80’ 6395 lb (2901 kg) 124” (3.14 m)
WARNING
Do not, under any circumstances, work at an elevated
height without using proper fall protection as required by
local, state, or federal regulations
REFERENCE ONLY