Komatsu WA320-5H, Operation & Maintenance Manual, Page: 57 / 321

PRECAUTIONS FOR MAINTENANCE
SAFETY
2-34
PRECAUTIONS WITH HIGH-PRESSURE OIL
The hydraulic system is always under internal pressure. When inspecting or replacing piping or hoses, always
check that the pressure in the hydraulic circuit has been released. If the circuit is still under pressure, it will lead to
serious injury, so always do as follows.
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When carrying out inspection and maintenance of the pressure, release the pressure before starting. For
details, see “MAINTENANCE WITH ENGINE RUNNING (2-30)“. Do not carry out inspection or replacement
work with the circuit under pressure.
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If there is any leakage from the piping or hoses, the surrounding area will be wet, so check for cracks in the
piping and hoses and for swelling in the hoses.
When carry out inspection, wear safety glasses and leather gloves.
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There is a hazard that high-pressure oil leaking from small
holes may penetrate your skin or cause blindness if it con-
tacts your eyes directly. If you are hit by a jet of high-pres-
sure oil and suffer injury to your skin or eyes, wash the
place with clean water, and consult a doctor immediately
for medical attention.
HANDLING HIGH-PRESSURE HOSES
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If oil or fuel leaks from high-pressure hoses, it may cause fire or defective operation, which may lead to serious
injury or property damage. If any loose bolts are found, stop work and tighten to the specified torque.
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If any damaged hoses are found, stop operations immediately and contact your Komatsu distributor.
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Replace all hoses every 2 years at the latest. The shelf life of the hose should not exceed 2 years.
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Hoses must be replaced as soon as the following damage is noticeable:
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damage to the outer layer through to the intermediate layer,
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brittleness in the outer layer,
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distortions in pressurised or unpressurised state not conforming with the original shape of the installed hose,
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leakages,
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damage to the hose fittings or to the connection between fittings and hose,
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storage damage.
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When replacing the hoses, always replace the O-rings, gaskets, and other such parts at the same time.
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See also "PERIODIC REPLACEMENT OF SAFETY CRITICAL PARTS (4-16)".