From Latham Marine:
‘Full Power Hydraulic System’ Bleeding: Ensure that all hydraulic lines and fittings are securely tightened before starting the bleeding process. During the entire bleeding process, check the oil level in the steering reservoir regularly and top up when necessary. DO NOT LET RUN DRY ! Turn on the engine or engines that are fitted with a power steering pump and let run for a few minutes without touching the steering wheel. With the power steering pump(s) running, turn the steering wheel hard-over in one direction and release the wheel. With a bucket placed under one of the steering cylinders, crack the hose fitting that is closest to the piston. This is the port that is closest to the piston rod when the rod is extended and the port that is farthest from the piston rod when the rod is retracted. Allow the oil to leak out of the fitting until there is a solid stream of oil, then tighten the fitting. With the steering wheel in the same position, repeat this step for any other cylinders. Check oil level in reservoir and top if necessary.
After tightening the cylinder hose fitting(s), turn the steering wheel ‘hard-over’ to the other side then release the wheel. Repeat the bleeding process at the cylinders as described above. Check oil level in steering reservoir and top if necessary.