looks like you will have to bleed it by loosening the fitting at the ram.
this you have to start with the ram hard over on the side you want to bleed.
ie the side you bleed, the chamber in the ram has no oil
in it with the steering
rod fully extended on that side,' lets call that side starboard .
(the oppsite side of the ram is full of oil
and as you turn the wheel this floes back to the pump reservoir.)
now with someone at the helm
,the ram hard over to starboard open the hose fitting fractionally,and turn the helm
slowly to port air and oil will spurt out,keep turning the wheel till only oil comes out then tighten the hose fitting once only oil is leaking.
keep turning till ram is hard over to port.
repeat process of loosening hose fitting on port side,turning wheel slowly to starboard until only oil escapes.
make sure to keep topping up helm reservoir with oil whilst turning wheel.
this should clear the air from the system,repeat if system still spongy.
if this was never done when you replaced the seals
then it is not surprising the steering
is not working!