Hydraulic System; Inspection And Maintenance Of Hydraulic Equipment - Hitachi ZW180 Operator's Manual

D. HYDRAULIC SYSTEM
INSPECTION AND MAINTENANCE OF HYDRAULIC
EQUIPMENT
CAUTION: 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 Be sure to relieve the air pressure from the hydraulic oil
tank by pressing air bleed valve (1).
3.3 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.
3.4 Keep body parts and face away from plugs or screws
when removing them.
Hydraulic components may be pressurized even when
cooled.
3.5 Never attempt to service or inspect the hydraulic cir-
cuits on slopes. They are highly pressurized due to self-
weight.
IMPORTANT:
• When connecting hydraulic hoses and pipes, take
special care to keep seal surfaces free from dirt and
to avoid damaging them. Keep these precautions
in mind:
• Wash hoses, pipes, and the tank interior with a
washing liquid and thoroughly wipe it out before
reconnecting them.
• Only use O-rings that are free of damage or de-
fects. Be careful not to damage them during reas-
sembly.
• Do not allow high pressure hoses to twist when
connecting them. The life of twisted hoses will be
shortened considerably.
• Carefully tighten low pressure hose clamps.
Do not overtighten them.
MAINTENANCE
7-40
1
M4GB-07-044