Hitachi ZX27U-2 Operator's Manual page 147

Bleed Air from Hydraulic System
After changing hydraulic oil, bleed air from the hydraulic
system by following the procedure described below.
Bleed Air from Pump
IMPORTANT: If the engine is started when the pump is
not filled with hydraulic oil, damage to
the pump may result.
1. Connect all hydraulic lines to the hydraulic pump. Fill
any hydraulic components, that can be filled with hy-
draulic oil, with as much hydraulic oil as possible at
this time.
2. Add hydraulic oil to the hydraulic oil tank to the speci-
fied level.
3. Check all line connections for any oil leaks. Set the
engine control dial or engine control lever in the slow
idle position.
4. Start the engine. Wait 5 to 10 seconds. Stop the en-
gine.
5. Check the hydraulic oil level at the level gauge lo-
cated on the side of the hydraulic oil tank. Add hy-
draulic oil if necessary.
6. Restart the engine. Confirm that hydraulic oil level in
the hydraulic oil tank is sufficient. Run the engine for
approximately 1 minute.
7. This is the end of the hydraulic pump air bleeding
procedure.
NOTE: If the hydraulic pump is left empty overnight or
longer, be sure to fill the pump with clean hy-
draulic oil before performing the air bleeding
procedure above.
Bleed Air from hydraulic circuits
1. After filling hydraulic oil in the hydraulic oil tank, start
the engine. Evenly operate each cylinder and swing
motor repeatedly for 10 to 15 minutes to purge air
from hydraulic system.
2. Position the machine in the hydraulic oil level check-
ing position.
3. Stop the engine. Check hydraulic oil level. Add oil as
necessary.
MAINTENANCE
7-27
ZX27U , ZX30U , ZX35U
-2 -2
ZX27U , ZX30U , ZX35U
-2 -2
ZX40U , ZX50U
-2 -2
ZX40U , ZX50U
-2 -2
Oil Filter
-2 M589-07-010
-2
M1M7-07-032
Oil Filter
M1LD-07-006
M1M7-03-004