My hangar neighbor (Zenith builder - DAR inspection this week!) had some Bakerseal that he used on his plane. He got it from Aircraft Spruce and is enough to last several lifetimes. It looks very similar to the paste compound you can get in the plumbing section at any hardware store, but says specifically that it is made for use with hydraulic fluid (and many other things.)
I took the leaking fitting out and cleaned it very well with a brush and some solvent. I also cleaned the female thread in the same manner until they were shiny. I then applied a liberal amount of the paste to all but the first thread and installed it. Reconnected everything and filled it.....Voila! Leak free.
On to the next item on the list....