[Rakthi]

These are the steps for the Fumotec Komatsu 490LC. Should be similar. After each movement of the pushrods in the cylinder I would top up the oil if the tank is really that small. I was surprised at the total amount of oil needed.


First steps for hydraulics commissioning:
-Mount all nipples using liquid gasket
-Disconnect the cylinder pushrods from the Excavator arms, so there is no load on the cylinders.
-Looking from the front of the excavator, make sure that the hydraulic pump runs in a clockwisedirection.
-Open (anti-clockwise) the ‘max’ pressure valve (the little brass valve) 2 or 3 turns
-Start the hydraulic pump with about 15-20% rpm
-Close the ‘max’ pressure valve slowly until you reach 10-15 bar on the pressure gauge.
-Now open the first valve a small amount in each directions, this should release the sealing rings in the cylinders (in case the cylinders have been stationary for a period of time). You should see the cylinders moving in each direction.
-Once the cylinders are free to move then operate the valve to move the cylinder to its end position. Now operate the valve to move the cylinder to the opposite end of its travel, you may hear air bubbles returning to the oil tank.
-Move the cylinder 5-10 times from one end position to the other until there is no air bubbles returning to the oil tank (you should see the air bubbles in the yellow tubes)
-Repeat this procedure for all other cylinders
-Once all the air has been eliminated from the system you can reconnect the cylinder pushrods to their mounting points. Increase the pressure in the hydraulic system to 20 bar and you should be ready to move the excavator arms.