National Crane Published 5-27-2018 Control # 039-06 5-3
800D SERVICE
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.
Hydraulic Oil Recommendations
For the hydraulic oil specifications, Reference Lubrication,
page 4-1.
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.
1. Remove the reservoir drain plug. Allow about three
minutes after hydraulic oil stops flowing from the drain
port for the side walls to drain.
2. Clean and install the reservoir plug and fill the reservoir
with a 50/50 mixture of fuel oil and clean hydraulic oil.
3. Cycle the crane through all functions several times.
Then return the crane to its stowed position and turn the
front and rear wheels to the extreme left. Shut down the
engine.
4. Remove the reservoir drain plug and drain the reservoir.
Clean and install the drain plug and fill the reservoir with
clean hydraulic oil.
NOTE: Hydraulic oil supply lines must be connected to the
cylinders when flushing the system.
Draining the various components will be aided by
connecting a drain line in place of the disconnected
return line.
5. Disconnect the return line from the lift cylinder and raise
the boom to maximum elevation.
6. Connect the cylinder return line and lower the boom to
its stowed position. Replenish the reservoir hydraulic oil
level as required.
7. Disconnect the return line from an outrigger extension
cylinder and fully extend the outrigger.
8. Connect the outrigger return line and retract the
outrigger. Replenish the reservoir hydraulic oil level as
necessary.
9. Repeat Steps 7 and 8 for the remaining outriggers.
10. Disconnect the return lines from a pair of outrigger jack
cylinders and activate the cylinders to their maximum
down positions.
11. Connect the return lines and raise the outrigger jack
cylinders to the stowed position. Replenish the reservoir
hydraulic oil level as necessary.
12. Repeat Steps 10 and 11 for the remaining two outrigger
cylinders.
13. Disconnect the return line from the telescope cylinder
and fully extend the boom.
14. Connect the return line and retract the boom. Replenish
the reservoir hydraulic oil level as necessary.
15. Disconnect the return lines from steer cylinders and turn
the wheels to the extreme right.
16. Connect the return lines and turn the wheels to the
extreme left and then back to center. Replenish the
reservoir hydraulic oil level as necessary.
17. Raise the crane on outriggers.
18. Disconnect the return line from the main hoist motor and
fully hoist up the hoist.
19. Connect the return line to the main hoist motor and fully
hoist down the hoist, then hoist up again. Replenish the
reservoir hydraulic oil level as necessary.
20. Disconnect one of the lines from the swing motor and
drive the motor in the direction it will go.
21. Connect the line to the swing motor, then drive the swing
motor in the opposite direction until the boom is centered
and forward. Replenish the reservoir hydraulic oil level
as necessary.
When hydraulic oils are changed, recheck the reservoir
hydraulic oil level after brief system operation and add
hydraulic oil as required. Ensure the crane is level and in the
travel mode of operation when the hydraulic system is being
filled. The system must be filled with all cylinders retracted.
CAUTION
When draining the outrigger cylinders, always operate
either both front or both rear cylinders together to prevent
twisting the crane.
CAUTION
When hydraulic oils are changed or added, ensure that
hydraulic oils of different manufacturers are of the same
specifications, however, discoloration (milkiness) may
occur. Mixing incompatible hydraulic oils may result in
improper operation or damage to the machine.
Fo
r
Reference
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