"After putting in 30 lbs of air I went topside expecting at least an ordeal of turning the wheel. The second turn the steering engaged and it seems to be fine. "
The reservoir can be leaking air pressure but not fluid, depending on where the leak is. As long as the entire system is filled with fluid (which is what the pressure in the tank ensures) the steering will work. The pressure in the reservoir has no effect on the steering per se. IOW, putting 10 psi in the tank or 40 psi has no effect on steering effort.
The indicated 5 PSI (which may have been less due to gauge error) was insufficient to keep the system fully filled but luckily, enough to not allow the fluid to drain back enough to require all the wheel turning/pumping.
Some tanks - I assume ALL but I don't know that - have a check valve that is supposed to prevent fluid from draining out of the system just because tank pressure is low. If there is no check valve, and the pressure is extremely low in the tank, the "weight" of the column of fluid in the tubing at the upper helm can be higher than the tank pressure so you lose upper helm steering first as the fluid drains back.The reservoir can be leaking air pressure but not fluid, depending on where the leak is. As long as the entire system is filled with fluid (which is what the pressure in the tank ensures) the steering will work fine. The pressure in the reservoir has no effect on the steering per se. IOW, putting 10 psi in the tank or 40 psi has no effect on steering effort.
The indicated 5 PSI (which may have been less due to gauge error) was insufficient to keep the system fully filled but luckily, not enough fluid had actually drained back to make any difference. Some tanks - I assume ALL but I don't know that for sure - have a check valve that is supposed to prevent fluid from draining out of the system just because tank pressure is low. If there is no check valve or it's faulty, and the pressure is extremely low in the tank, the "weight" of the column of fluid in the tubing at the upper helm can be higher than the tank pressure so you lose upper helm steering first as the fluid drains back. If there is a bit of pressure in the tank, fluid can fall below the level of the upper helm pump but not to the level of the lower helm pump.
