Komatsu 114E-3 Series, Руководство по ремонту, Страница: 144 / 342

SEN00457-01 40 Troubleshooting
2
114E-3 Series
General information on troubleshooting 1
Points on troubleshooting 1
k
Stop the machine in a level place, and check that the safety pin, blocks, and parking brake are
securely fitted.
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 coolant 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 con-
nect it properly.
The aim of troubleshooting is to pinpoint the basic cause of the failure, to carry out repairs swiftly, and to pre-
vent 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 questions to form some idea of possible causes of the failure that would produce the reported symp-
toms.
1. Do not rush at disassembling the machine even if a failure occurs.
Otherwise,
q
Parts that have no connection with the failure or other unnecessary parts will be disassembled.
q
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 investigation and to carry out troubleshooting in accordance with the fixed pro-
cedure.
2. Questions to users and operators
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. Inspections 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) Check other maintenance items which can be visually checked and are considered necessary.
4. Confirmation of failure
Confirm the degree of failure on your own to verify if it is a real failure and the machine is handled or
operated improperly.
a
When operating the machine to reenact the troubleshooting symptoms, do not carry out any inves-
tigation or measurement that may make the problem worse.
5. Troubleshooting
Pinpoint high possibility causes according to the results of examinations and inspections of items 2 to 4,
and find the failure location based on the troubleshooting table or troubleshooting flow (chart).
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 information.
6. Radical countermeasures against failure cause
Even if the immediate problem is removed, a similar failure will reoccur unless its root cause is removed.
To prevent reoccurrence, examine the reason of the failure cause occurrence and remove the root
cause.