My 28 years old Scheel-designed, Morgan-built 45' ketch has been having some hydraulic steering problems. It all began with loss of air pressure + fluid in the hydraulic fluid reservoir. Refilling and re-pressurizing made the system operational again, but only for 5-6 hours. A leak somewhere was suspected but none could be found, reason why we ended up replacing most of the copper tubing in the system and rebuilding the cylinders, following which a new problem cropped up: we could bleed the air out of the port turn side (as per instructions), but not completely out of the starboard turn side. This has left us with unreliable steering capabilities. The opinions of the "experts" vary from: "you don't know what you're doing" (bleeding the air out of the system, even though we have successfully done it many times before), "a bad air venting box", "a bad helm steering pump" (at the binnacle), "the autopilot's pump has been installed wrong" (even though it has been working fine for 28 years and the exisiting pump is only 7 years old). Has any poor soul out there had similar problems and if so, what was the cause and the solution. Your opinions will be greatly appreciated. Raf "I can teach a man how to sail; I cannnot teach him why".