FastEddieR
Bronze Member
The air will purge while the system in in use. Extending and retracting the cylinders causes the air to move to the reservoir where it comes out of the solution. They hydraulic system is a closed loop for the most part (beyond the valves) the reservoir is not pressured like the lines are beyond the pump and valve system. If you don't cycle the fluid (by extending/retracting the cylinders) the air bubbles stay in the supply and return lines & cylinders and don't make it to the reservoir.