Komatsu Galeo PC800-8, Shop Manual

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PC800, 850-8
SEN00789-02 40 Troubleshooting
General information on troubleshooting
Points to remember when troubleshooting
k
Stop the machine in a level place, and check that the safety pin, blocks, and parking brake are securely fit-
ted.
k
When carrying out the operation with 2 or more workers, keep strictly to the agreed signals, and do not allow
any unauthorized person to come near.
k
If the radiator cap is removed when the engine is hot, hot water may spurt out and cause burns, so wait for
the engine to cool down before starting troubleshooting.
k
Be extremely careful not to touch any hot parts or to get caught in any rotating parts.
k
When disconnecting wiring, always disconnect the negative (–) terminal of the battery first.
k
When removing the plug or cap from a location which is under pressure from oil, water, or air, always release
the internal pressure first. When installing measuring equipment, be sure to connect it properly.
The aim of troubleshooting is to pinpoint the basic cause of the failure, to carry out repairs swiftly, and to prevent
reoccurrence of the failure. When carrying out troubleshooting, and important point is of course to understand
the structure and function. However, a short cut to effective troubleshooting is to ask the operator various ques-
tions to form some idea of possible causes of the failure that would produce the reported symptoms.
1. When carrying out troubleshooting, do not hurry
to disassemble the components.
If components are disassembled immediately
any failure occurs:
•
Parts that have no connection with the failure
or other unnecessary parts will be disassem-
bled.
• It will become impossible to find the cause of
the failure.
It will also cause a waste of manhours, parts, or
oil or grease, and at the same time, will also lose
the confidence of the user or operator. For this
reason, when carrying out troubleshooting, it is
necessary to carry out thorough prior investiga-
tion and to carry out troubleshooting in accor-
dance with the fixed procedure.
2. Points to ask user or operator
1) Have any other problems occurred apart
from the problem that has been reported?
2) Was there anything strange about the
machine before the failure occurred?
3) Did the failure occur suddenly, or were there
problems with the machine condition before
this?
4) Under what conditions did the failure occur?
5) Had any repairs been carried out before the
failure?
When were these repairs carried out?
6) Has the same kind of failure occurred
before?
3. Check before troubleshooting
1) Is there any sign of irregularities of the
machine?
2) Make checks before starting day's work.
3) Make checks of other items.
4) Other maintenance items can be checked
externally, so check any item that is consid-
ered to be necessary.
4. Confirming failure
Confirm the extent of the failure yourself, and
judge whether to handle it as a real failure or as
a problem with the method of operation, etc.
a
When operating the machine to reenact the
troubleshooting symptoms, do not carry out
any investigation or measurement that may
make the problem worse.
5. Troubleshooting
Use the results of the investigation and inspec-
tion in Items 2 – 4 to narrow down the causes of
failure, then use the troubleshooting table or
troubleshooting flowchart to locate the position
of the failure exactly.
a
The basic procedure for troubleshooting is
as follows.
1] Start from the simple points.
2] Start from the most likely points.
3] Investigate other related parts or infor-
mation.
6. Measures to remove root cause of failure
Even if the failure is repaired, if the root cause of
the failure is not repaired, the same failure will
occur again.To prevent this, always investigate
why the problem occurred. Then, remove the
root cause.