There are really only two ways a soft solder joint can fail when we're talking about mechanical things instead of plumbing. The first is to have the two parts moving back and forth to squeeze the solder back and forth until it work hardens and breaks. That's the result of a badly fitted joint. The second is for corrosion to weaken the parts themselves, which can happen with acid flux if you don't wash it off after you're done. To test your joint, all you have to do it put the thing together and wiggle it. If you are able to make the parts move hardly at all, then it's not right. So for clevises, you'll need to be sure that the wire you're soldering in is sized well to the clevis itself. For things that can't make a good mechanical connection like a loose socket connection or trying to join two pieces of music wire for a landing gear without wrapping them in fine copper wire, brazing rod is the right stuff to use because the filler is nearly as strong as the material and will tolerate the stress that soft solder will not.