SUCCESS! The locknuts are loose! How was that accomplished?
Though I didn’t have any of the suggested brands of penetrating oil, I did have some Liquid Wrench. So I put some on several times and let it soak in. The 90+ degree day probably didn’t hurt.
One of my 3/4-inch wrenches was shorter than the other. So I put that one aside and selected a larger wrench with a longer handle. Then I put on some gloves.
I put the 3/4-inch wrench on the lock nut and the larger wrench on the hook end of the threaded rod. Making sure that my gloved hands were as close as possible to the end of each wrench, I pulled the wrenches toward each other as hard as I could.
Suddenly, the wrenches fell off and the nut was loose! Hurrah!
Thanks for your help, everyone. I think the penetrating oil, the gloves, and the increased leverage of the longer wrenches did the trick.
A further note: When we bought the camper, the HappiJac turnbuckles were installed upside down. HappiJac recommends they be installed with the threaded rod up so rain water does not run down into the business end of the cylinders. Also, when penetrating oil is applied, it will run down toward the locknut instead of away from it.
