I while back I started a thread about rebuilding vs replacing my Hynautic clutch and throttle system. I had heard that it was not a good idea to rebuild the Hynautics because you would never get all the crud out of the “fluid”. My fluid was reportedly black and nasty. We flushed all four lines and someone in VA (I think) rebuilds the other Hynautic components. After about 15 hours of operation I am very pleased. The controls are much easier to manipulate. Easy and smooth. An improvement for docking as I can shift both engines individually with one hand. Before I had to shift 1 engine with one hand. I don’t have the invoice yet but was told to figure about 14,000. Bottom line is; if my 500 hours of operation are like my first 15 then this is a big improvement and it appears if the right person does the rebuild that one can get very good results from rebuilding the Hynautic system and not have to go electric and risk the perils associated with them.
I'm glad it worked out for you. I went thru this on my buds Hatt. I kept all the control fluid that was drained from his Hynautic project. Stored it in 2L coke bottles. That black gunk settled to the bottom of the bottles and I kept pouring the fluid into fresh bottles (less that last 1/4" with the gunk) with a coffee paper filter rig I made up. I now have 97% of the control fluid I purchased. Good thing too, No more official Hynautic HA5455 control fluid left anywhere. Dometic drew the last drop of Hynautic blood and buried the product.