those damn scissor jacks

If they're on a class c just take them off and junk them. One month later you won't see any difference.

DuPont makes 2 products that are very similar to each other and actually may be the same thing.
DuPont Teflon Chain Saver - dry self-cleaning lubricant (for bicycles)
Dupont Teflon Non-Stick - dry film lubricant.

I have used the Non-Stick for several years with success. Not sure I would use it inside of a lock; may tend to gum it up.

You may want to try one of these products after you thoroughly clean the threaded rod on you jacks.

Ray

Funny, it seems to me all jacks are getting harder to turn and the wheels are getting harder to lift into place. It couldn't be me getting old, could it?

Funny this subject came up. Just this morning I had my SIL remove mine. I'm going to use some small bottle jacks instead.

On some jacks the nut that the threaded rod goes through has to swivel to compensate for the changing angle. If it's bound in some way it will be harder to turn the rod.

I just sprayed mine with wd40 to clean up all the gunk and then wiped lithium grease on moving parts. Night and day difference in how easy it was to work the jacks.

When we had our 5'er, I used a 18V cordless drill with socket adapter to raise/lower the scissor jacks on the rear. I set the clutch so the drill would not over tighten the jack.

Once the threads are clean and dry, grease is the lube of choice. Penetrating oil does not lubricate as well in this situation. Make sure the thrust bearing is lubed too. It is on the screw by the end that is closest to you when cranking it. A bit of motor oil on the hinges will also help.

Wire brush and clean with brake or carb cleaner, wire brush again and when fully clean spray some Slideout spray on them. Mine required an "ELL" shaped handle at the end so I brazed a little to an impact socket and used my electric impact wrench to operate. Impact was for loosening lug nuts etc. I used a 1/2 torque wrench to tighten.