Seacraft 23Wa with Hynautic powersteering question

[gss036]

My 1989 Seacraft came with above system and has been trouble free since new. I looked at the reservoir today which is in the rear starboard storage hole beside one of the batteries. The pressure guage has rusted to the point that the needle has fallen off. How would one go about repairing this. There is a standard air fitting on it also, so I would think you would have to release the pressure 1st.
The steering still works ok, but I wonder how long before I get a leak? I think it used to read about 25 #'s.
I know that Seastar now owns and replaces parts for the system. Looking for advice before I try to dig into something I know absoultely nothing about. [img]/images/graemlins/confused.gif[/img] [img]/images/graemlins/frown.gif[/img]