Hydraulic System; Inspection And Maintenance Of Hydraulic Equipment - Hitachi ZW 370-6 Operator's Manual

D. Hydraulic System

Inspection and Maintenance of Hydraulic Equipment

d
CAUTION: During operation, the parts of the hydraulic
system become very hot.
Allow the machine to cool down before beginning
inspection or maintenance.
1. Park the machine following the same procedures as
described on page 7-6 for preparation of inspection/
maintenance work.
2. Begin servicing hydraulic components only after
components, hydraulic oil and lubricants are completely
cooled, and after releasing residual circuit pressures.
2.1 Release internal pressure.
2.2 Be sure to relieve the air pressure from the hydraulic oil
tank by pressing air bleed valve (1).
2.3 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.
Keep body parts and face away from plugs or screws
when removing them.
Hydraulic components may be pressurized even when
cooled.
Service only on a flat, solid and level surface.
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 defects. Be
careful not to damage them during reassembly.
 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.
 When adding hydraulic oil, always use compatible oils;
do not mix brands of oil. The machine is filled with
Super EX 46HN when it is shipped from the factory.
When selecting to use another brand of oil listed in the
table "Hydraulic Oil", be sure to completely replace the
oil in the system.
 Do not use hydraulic oils other than those listed in the
table "Hydraulic Oil".
 Never run the engine without oil in the hydraulic oil
tank.
MAINTENANCE
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95Z7B-7-40-1