I am putting my watermaker back together finally, after an 13 month delay....darned hurricanes. I assembled the membranes and dry fitted everything to do a first run test. I didn't use any sealant on the flares and had no leaks there at 60 Bar. Only ran the unit for a few minutes to test the rebuild pump and determine if there were any gross leakage issues so can't say if the Locktite is needed or not. I will apply some when I am satisfied the system is ready to run.
A word of caution, I had new HP hoses made up in a shop in the US. They reused the end fittings but did not reapply them to the new hoses correctly. They did this behind the counter where I did not observe, again we should watch the workers. The fitting near the HP pump leaked on the second application of pressure around 20Bar. Upon inspection we found the inner hose lining cut away to make the fitting slide in easier. The tech never disassembled the fitting and simply shoved the hose into the metal while turning it. We were lucky that I am used to commissioning new engineering projects and want eyes on all hoses and fittings until broken in.
We bought ready made HP hoses at Caraib Marine which eliminated entirely the questionable refitted hoses.
SV Annie SM 37
Le Marin, Martinique