Fiat Kobelco EX355 Tier2, Technical Manual

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T5-4-48 EX355
TROUBLESHOOTING B
F-10 Front Attachment Cylinder Drift is Large.
Related Fault Code: None
•
Boom Cylinder Internal Leakage Check
1. With the bucket cylinder fully retracted and the arm
cylinder slightly extended from the fully retracted
position, lower the bucket tooth tips onto the
ground.
2. Disconnect hoses to the boom cylinder rod side.
Then, drain oil from hoses and cylinders. (Plug the
disconnected hose ports.)
3. Retract the arm cylinder to lift the bucket above the
ground.
At this time, if oil flows out of the pipes from which
the hoses were disconnected and the boom cylin-
der is retracted, internal leakage in the boom
cylinder exists.
If no oil flows out of the pipes from which the hoses
were disconnected but the boom cylinder is re-
tracted, internal leakage in the control valve exists.
SM0636
NO
YES
Check if each
front attachment
cylinder drift is
within the
specified value.
NO
YES
Check if needle
valve in boom 1
section in 4-spool
control valve is
completely
closed.
NO
YES
Close needle
valve.
Normal
Check if the
cylinder drift is
reduced when
pilot shut-off
valve is closed.
Faulty pilot valve
Check if the
symptom is
deleted when the
overload valve is
temporarily
switched with
one in an other
cylinder circuit.