My Mistral 33 was built in 1972 and has its original hydraulic steering. The steering has been somewhat problematic for a while. It's been increasingly difficult, if not impossible, to bleed all the air from the hydraulic lines. Last summer I had an auto pilot installed but it wouldn't work and seemed to aggravate the problem with air in the lines. The boatyard has since informed me that it won't work on my boat, that my hydraulic system is old and complicated and that I should consider replacing the steering system to eliminate the hydraulics altogether. I would prefer to avoid that expense but have no information about the technical aspects of the existing system to know if it can be repaired or updated in some fashion. Any information would be greatly appreciated.