SUCCESS removing frozen lock nuts on HappiJac turnbuckles

If you are referring to the spring-loaded cylinders, the HappiJacs have been on my camper for ~14 years and they are rusty. they get removed only once or twice each year. A couple squirts of PB Blaster over a couple days, and then a pair of 3/4 open end wrenches placed closely together so you can grab them and 'make a fist' has always freed the top nut for me. Once loose, I've also chased the threads with a die and greased the threads on assembly.