Bleeding Air From Hydraulic System - Hitachi ZX200-5G Workshop Manual

Bleeding Air from Hydraulic System

Bleed air from the hydraulic system as follows when
hydraulic oil has been drawn, the suction filter and
suction pipe have been replaced, or the pump device,
swing motor, travel motor, cylinders have been removed/
installed.
IMPORTANT: If air is accumulated inside of the pump
and if the engine starts in lacking of hydraulic oil,
the pump may be damaged.
 Bleeding Air from Pump
 Remove the air bleed plugs on top of the pump. Add
hydraulic oil to the pump.
 After the pump is filled with hydraulic oil, temporarily
tighten the plugs. Then, start the engine and run it at
slow idle speed.
 Slightly loosen the plugs and bleed air from the
pump until hydraulic oil comes out from the gap.
 After bleeding all air, securely tighten the plugs.
IMPORTANT: If air is accumulated inside of the motor
and if the engine starts in lacking of hydraulic oil,
the motor may be damaged.
 Bleeding Air from Travel Motor, Swing Motor
 Remove the air bleed plug (top) from the travel
motor and swing motor. Fill the motor case with
hydraulic oil.
SECTION 1 GENERAL
Group 4 Bleeding Air
IMPORTANT: If air is accumulated inside of the
cylinder and if the cylinder is operated suddenly
in lacking of hydraulic oil, the seal may be
damaged or the cylinder may seize.
 Bleeding Air from Hydraulic Circuit
 After refilling hydraulic oil, start the engine. While
 As the pilot circuit has an air bleed device, air in the
 Reset the front attachment in position for checking
 Stop the engine. Check hydraulic oil level. Replenish
W1-4-1-2
operating each cylinder, swing motor, and travel
motor evenly, operate the machine under light loads
for 10 to 15 minutes. Slowly start each operation
(never fully stroke the cylinders during initial
operation stage).
pilot circuit will be bled while performing the above
operation for approx. 5 minutes.
hydraulic oil level.
hydraulic oil if necessary.