Hydraulic System; Inspection And Maintenance Of Hydraulic Equipment - Hitachi ZW 120-6 Operator's Manual

D. Hydraulic System
Inspection and Maintenance of Hydraulic
Equipment
d
CAUTION: When checking and/or servicing the
hydraulic components, pay special attention to the
following points.
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 7-7 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 pressure.
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.
Never attempt to service or inspect the hydraulic
circuits on slopes. They are highly pressurized due to
self-weight.
MAINTENANCE
1
7-39
MNSC-07-013