National Crane 600H, Service Manual

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2
NATIONAL CRANE
08-19-2022 Control # 092-13
2-7
600H SERVICE MANUAL HYDRAULIC SYSTEM
reservoir has an internally mounted full flow filter and integral
baffles that help cool the hydraulic oil and prevent foaming.
Hydraulic oil flows through the suction line at the lower front
of the reservoir to the hydraulic pump. Most of the return flow
goes through the filter at the top of the reservoir.
A magnetized drain plug in the bottom of the reservoir
collects metal particles from the hydraulic oil if it becomes
contaminated.
A sight gauge is located on the side of the reservoir and has
a decal that indicates a “full” level and an “add oil” level. 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.
A filler cap on the top of the reservoir is for filling the
reservoir. The filler cap includes a strainer for catching
contaminants and gaskets to prevent leaking. A breather cap
(vent) which is part of the filler cap allows air to enter or leave
the reservoir. The breather must be kept clean to prevent
damage to the reservoir.
A large access cover on the top of the reservoir provides
access for cleaning. The cover is secured to the top of the
reservoir with screws and has a gasket to prevent leaking.
The access hole can also be used to fill the reservoir after it
has been completely drained.
The hydraulic oil filter is located in the reservoir and bolts to
the top of the reservoir. The filter housing contains a
replaceable filter element.
A filter element gauge on the filter head indicates how
restricted (clogged) the filter element is. When back pressure
caused by a dirty filter element exceeds 15 psi (103 kPa), the
filter head’s bypass feature allows the hydraulic oil to bypass
the filter and flow into the reservoir.
Hydraulic Filter Replacement
The filter is mounted in the oil reservoir, and is a replaceable
element type (Figure 2-1).
The filter must be serviced with National Crane replacement
elements at recommended intervals to assure the warranty
remains in effect.
Element Removal
1. Shut down the hydraulic system.
2. Wipe any dirt from the filter head and cap assembly.
3. Loosen the six bolts securing the filter cap to the filter
head.
4. Twist to unlock and remove the filter cap.
5. Remove the filter element from the filter bowl (housing).
6. Ensure the new filter element is correct by comparing
their part numbers with the part numbers of the used
filter element.
7. Discard the used filter element.
DANGER
Ensure that hydraulic system is shut down and the
pressure is relieved.
!
REFERENCE ONLY