OK, so i went to try the method by the book. I mean the Honda service manual.
As i over hauled the PS pump, so the pump was completely empty on refill. Has tough time bleeding out the air. It was blowing air back into the reservoir due to air being compressed inside.
Had to suck air out from the drain pipe attached with my mouth(recommended is hand vacuum pump).
I believe to overcome this situation, Honda dealer had developed the new technique to replace the fluid.