I don't know much about hydro steering, but is it a one way filter? Make sure the flow is the right direction. I assume the lines are new and not clogged. I would start disconnecting lines and make sure you are getting fluid to both sides of the cooler and so forth. I dont know if you can bleed them like regular ps systems. With that, you ust leave the cap and yurn the wheel back and forth till the res. stays full.