Bruce, I was thinking WD-40 but a "deep penetrating lubricant soaking the joint and leaving overnight" would certainly be better. What would be an example of that?
If you can share the brand/product that would be great. Thanks!
I used SeaFoam Deep Creep which is available at Auto Stores and Walmart, there are a number of penetrating oils around and WD40 would work too, just leave it overnight to soak in.