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GENERAL / Bleeding Air from Hydraulic Oil Tank BLEEDING AIR FROM HYDRAULIC OIL TANK CAUTION: Escaping fluid under pressure can penetrate the skin and eyes, causing serious injury. Avoid this hazard by relieving pressure before disconnecting hydraulic lines. Hydraulic oil may be hot after operation and may spurt, possibly causing severe burns. Be sure to wait for oil to cool before starting any repair work. The hydraulic oil tank cap may fly off due to remaining pressure if removed quickly. Slowly loosen the cap to release any remaining pressure completely. Preparation 1. Park the machine on a level solid surface. Lower the front attachment to the ground. M104-07-021

2. After stopping the engine, move the control levers several times to release any pressure remaining in the system. Rotate the hydraulic oil tank cap approx. 30 counterclockwise using a hexagon wrench to release the trapped air in the hydraulic oil tank. Refer to Bleeding Air from Hydraulic System on page W1-1-2. : 4 mm


4. Remove the hydraulic oil tank cap. Connect a vacuum pump and operate it continuously to maintain negative pressure in the hydraulic oil tank. NOTE: Run the vacuum pump continuously while working on the hydraulic system.



Hitachi zaxis 450lch excavator service repair manual  
Hitachi zaxis 450lch excavator service repair manual