if the hangers are opposite each other down the run,cut a piece of rod and place it between the 2 vertical rods on the horizontal.kindorff! cut to catch both threaded rod drops to the hangers,cut one to test the space between pipes,and just go down the line.(if hangers are exsistiing)you want cut the kindorff so the hole is just cut so to accept the rod as you pinch it in between the rods.
Have you considered up the size of the rod to half " ?
And for those of you in "Rio Lindo" Kindorff is the slotted green U chanel bar,there are some other heavier gauge U channels outhere,up north where I'live we refered to it as kendorff AKA hanger strap.
You can see the mess this is. These joints have loosened twice (and will again) because of the piping moving and loosening the gaskets. There is absolutely nowhere to anchor to so we need to solidly join these together.
what's the blue stuff ? its locktite? I' dont fully understand how and why the joints are coming loose ,but I' would try some thread lock and maybe a join expansion arrestor or a vibration absorber.
I' also got an idea from the posted picture ,Can you use a couple of victaulic flanges or couplings install 'em at the very far end of the joins and link them with threated rod?
Tough to tell what you got, it looks to me like 1 1/2 galvy tied to 1 1/4 galvy with a dresser reducer coupling and then a 1 1/4 threaded valve?
It looks like a tough place to re-pipe with new threaded or welded or soldered pipe but thats probably what you'll have to do to prevent the pipes from pulling apart (unless lateral movement is required).
Dresser couplings are easy to install but they dont make a solid connection.