Dick, dock neighbors had one of their YS castings break and they found it difficult to source 2nd hand parts. However, they had a local metal shop construct a replacement and that proved a cheap/easy fix.
As for your broader Q - should you keep the YS hardware given that its upkeep is proving time consuming and the results disappointing - that's eventually why I gave up on the 30 year old Edson pedestal and replaced it like-for-like with their Classic model. I came to a different conclusion than Charles and got about 5 years out of a repaint job by using International's 2-part metal prep product, followed by several coats of Brightside. The two-part metal prep seems to be quite effective over the years on a variety of aluminum hardware. I got 10 years out of the Bomar aluminum hatch frames with the same combo, but I think that's because it's simply harder to truly prep all the pedestal surfaces and there a mix of metals in the pedestal that are more noble. When refurb'ing WHOOSH, I thought back to how much time I spent while on the S coast of England, prepping and painting the pedestal, thought about the need to replace the bearings, control cables and looked at the rust on the underdeck pedestal plate (all of which meant tearing things apart anyway), and decided WHOOSH deserved new gear vs. another time-limited paint job.
BTW Edson does run sales and I lucked into one that both dropped the replacement parts by several hundred dollars and gave me a $100 credit on other merchandise. As it happened, I forgot to order a compass plate on which to mount the old compass to the new pedestal...so by using the credit that was another savings. The guys at Edson were a delight to work with; you might explore your options with them, and what timing makes sense.