Hitachi ZW 550-G, Technical Manual

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00-19
General Information
Outline
Cautions regarding welding repair service
If welding is needed to repair the chassis, observe the
following precautions to protect the hydraulic cylinders,
hydraulic units, gear sets, and electrical units from pos-
sible damage.
Cautions
1. Turn the starter switch OFF.
2. Remove the battery terminals both positive and
negative sides from the battery.
3. Disconnect the connectors for SCU (transmission
controller), ECM (engine controller), air conditioner
and tachometer converter as per Cummins Engine
Co.
4. Ground the welder near the section to be welded.
5. To ground the welder, check that the electric current
will not flow through the cylinders.
Cylinder head covers for some models have a low
conductive metal that will cause spark if the welding
current flows through it. The spark may damage
the cylinder rod or other parts.
6. Calibrate throttle pedal to ECM.
(a) Turn the starter switch to "ON".
(b) Fully depress and release the throttle pedal
three times.
(c) Turn the starter switch to "OFF".
Example 1
Example 2
35C00002
Section to be welded
Ground this section.
(correct grounding)
Do not ground this section.
Electric current may flow
through the cylinders.
35C00006
Section to be welded
Ground this section.
(correct grounding)
Do not ground this section.
Electric current may flow
through the cylinders.