Bleed Air From The Hydraulic System - Hitachi ZW 550-6 Operator's Manual

7. Supply hydraulic oil through filling port (3) while
checking the oil level at level gauge (6).
Refer to "Kinds of Oils" - "Hydraulic Oil" on page 7-16.
* Capacity of
hydraulic oil tank
300 liters
(79 gallons)
* At level gauge center (Tank capacity: 398 L (105 gal)
8. While filling oil into the hydraulic tank, make sure the
oil coming out of bleed screws (A, B) does not contain
air bubbles.
f
NOTE: When the secondary steering system is used, also
check the oil from bleed screw (C).
IMPORTANT: When changing hydraulic oil, take care
not to permit foreign matter such as dirt, water, and
/or sand to enter into the hydraulic oil tank.

Bleed Air from the Hydraulic System

9. After changing hydraulic oil or replacing the return
filter, pilot filter and/or suction filter, bleed air from
the hydraulic system following the procedures below.
9.1 After supplying oil, start the engine. Do not exceed
1000 RPM (min ). Move the bucket and lift arm
-1
cylinders several times to bleed air mixed in the
hydraulic circuit. Do not operate the cylinders
to the end of cylinder stroke, and do not apply a
heavy load to the cylinders.
9.2 Rest the bucket on the ground to resume the
hydraulic oil level check position.
9.3 Stop the engine. Check the oil level. Add oil as
needed.
10. Stop the engine. Check for any oil leakage. Check the
oil level using level gauge (6).
MAINTENANCE
Total oil capacity in
the hydraulic system
550 liters
(145 gallons)
6
7-45
115Z7-7-39-1
A
115Z7B-7-23-3
115Z7B-7-43-1
C
B