Quote Originally Posted by Pascal View Post
if Hynautics, you simply ran out of air pressure. just pump it back up (fitting on top of reservoir) with a bicycle hand pump to about 20 psi.

checking air pressure on Hynautics (steering or engine controls if equipped) is part of the preflight check.

once you pump it back up, turn the wheel to port until it re primes itself and locks, then back to stbd and you shoudl be fine.

could be a minor leak, just top it of once in a while, not worth hunting.
Per my Hynautics Manual, "...the resovoir stores approximately 2 quarts of hydraulic fluid under a pressure of 20 psi.". Purging system, "...use ATF Type "A" (its an old manual from the early 70's) or MIL SPEC MIL-0-5606 Aircraft Hydraulic Fluid...". "The resovoir is fitted with a 10 micron filter (never knew that)...". Fill to within 3" from top of the sight glass...and... pump the resovoir to 20-30psi.

I myself keep it at 30psi. It never lose pressure or fluid, since I had my flybridge unit send into Hynautic and rebuilt. Before that was leaking over the topsides.