HYDRAULIC SYSTEM
NBT40 SERVICE MANUAL
2-4
Published 8-01-2017 Control # 287-11
MAINTENANCE
General
Before adjustments and repairs are started on a crane, the
following precautions shall be taken as applicable:
•
Place a warning tag in a conspicuous location at the
controls stating that the machine requires adjustment or
repair before it can be operated.
•
Park the crane where it will cause the least interference
with other equipment or operations in the area.
•
Place all controls at the off position and set the brakes to
prevent inadvertent motion.
•
Disable all methods used to start the truck's engine.
•
Lower the boom to the ground or otherwise secured
against dropping.
•
Lower the hook block to ground or otherwise secured
against dropping.
•
Relieve the hydraulic pressure from all hydraulic circuits
before loosening or removing hydraulic components.
After adjustments and repairs have been made, do not return
the crane to service until all guards have been reinstalled,
trapped air removed from the hydraulic system if required,
safety devices reactivated, and maintenance equipment and
all warning tags removed.
Adjustments and repairs shall be done only by designated
personnel who are properly trained. Use only National Crane
supplied parts to repair the crane.
Hydraulic System Maintenance Precautions
Contaminants in a hydraulic system affect operation and
result in serious damage to the system components. Dirty
hydraulic systems are a major cause of component failures.
If evidence of foreign particles is found in the hydraulic
system, flush the system.
Disassemble and reassemble hydraulic components on a
clean surface.
Clean all metal parts in a nonflammable cleaning fluid. Then
lubricate all components to aid in assembly.
Inspect all sealing elements (O-ring, gaskets, etc.) when
disassembling and assembling the hydraulic system
components. Installation of new sealing elements is always
recommended.
When installing metal hydraulic tubes, tighten all bolts finger
tight. Then, in order, tighten the bolts at the rigid end, the
adjustable end, and the mounting brackets. After tubes are
mounted, install the hoses. Connect both ends of the hose
with all bolts finger tight. Position the hose so it does not rub
the machine or another hose and has a minimum of bending
and twisting. Tighten bolts in both couplings.
Due to manufacturing methods, there is a natural curvature
to a hydraulic hose. The hose should be installed so any
bend is with this curvature.
In case of replacement hoses with angled stem reusable
fittings, the hose curvature must be taken into consideration
when assembling and positioning the angled stem.
Label Parts When Disassembling
When removing or disconnecting a group of wires or cables,
tag each one to ensure proper identification during re-
assembly.
When shims are removed, tie them together and identify
them as to location. Keep shims clean and flat until they are
reinstalled.
Welding Precautions
Sensitive truck computer system and crane's electrical
system may be damaged by welding on the truck or crane.
The following precautions should be taken:
-
Disconnect truck battery cables.
-
Attach welding ground lead as close as possible to
area to be welded.
The hydraulic oil reservoir has a sight gauge located on the
side of the reservoir. This sight gauge has a decal beside it
that indicates a “full” level and an “add oil” level. The oil
required to bring it from the “add” line to the “full” line is 5
gallons. Do not fill the reservoir above the “full” line. The oil
level should be checked with the crane parked on a level
surface, in the transport condition (all cylinders retracted and
boom stowed) and the oil cold.
PARTS REPLACEMENT
Parts found damaged or out of tolerance when maintenance
is being performed need to be replaced. Refer to the
M a n i t o w o c C r a n e C A R E P a r t s C a t a l o g f o r p r o p e r
replacement parts.
SERVICE
Hydraulic Oil Recommendations
For hydraulic oil specifications, Reference Section 8 -
LUBRICATION.
Draining and Flushing
If a component has been changed because of a failure that
might allow metal or abrasive particles to enter the system,
all systems must be thoroughly checked, drained, and
flushed.
Reference Only
Содержание National Crane NBT40 Series
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Страница 136: ...HOIST NBT40 SERVICE MANUAL 5 14 Published 8 01 2017 Control 287 11 THIS PAGE BLANK R e f e r e n c e O n l y ...
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Страница 214: ...CRANE INSTALLATION NBT40 SERVICE MANUAL 9 36 Published 8 01 2017 Control 287 11 7488 4 7488 6 R e f e r e n c e O n l y ...
Страница 216: ...SCHEMATICS NBT40 SERVICE MANUAL 10 2 THIS PAGE BLANK R e f e r e n c e O n l y ...
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