Inspection And Maintenance Of Hydraulic Equipment - Hitachi Zaxis 850LC-3 Operator's Manual

INSPECTION AND MAINTENANCE OF
HYDRAULIC EQUIPMENT
IMPORTANT: Do not adjust the engine governor and/or
hydraulic components.
WARNING: During operation, the parts of the hydrau-
lic system become very hot.
Allow the machine to cool down before beginning in-
spection or maintenance.
1. Be sure that the machine is parked on a level, firm surface
before servicing hydraulic equipment.
2. Lower the bucket to the ground and stop the engine.
3. Begin servicing hydraulic components only after compo-
nents, hydraulic oil and lubricants are completely cooled,
and after releasing residual pressure.
3.1 Bleed air from the hydraulic oil tank to release internal
pressure.
3.2 Allow the machine to cool down.
Note that servicing heated and pressurized hydraulic
components may cause hot parts and/or oil to fly off or
escape suddenly, possibly resulting in personal injury.
3.3 Keep body parts and face away from plugs or screws
when removing them.
Hydraulic components may be pressurized even when
cooled.
3.4 Never attempt to service or inspect the travel and swing
motor circuits on slopes. They are highly pressurized
due to self-weight.
3.5 Even after bleeding the air from the hydraulic oil tank,
pressure remains in the various circuits of the hydrau-
lic system. Be sure to operate each control lever a few
times to release residual pressure from the system.
4. When connecting hydraulic hoses and pipes, take spe-
cial care to keep seal surfaces free from dirt and to avoid
damaging them. Keep these precautions in mind:
4.1 Wash hoses, pipes, and the tank interior with a washing
liquid and thoroughly wipe it out before reconnecting
them.
4.2 Only use O-rings that are free of damage or defects. Be
careful not to damage them during reassembly.
4.3 Do not allow high pressure hoses to twist when con-
necting them. The life of twisted hoses will be short-
ened considerably.
4.4 Carefully tighten low pressure hose clamps.
Do not over tighten them.
MAINTENANCE
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