I'll jump in as Larry is on the road to Coronado races today.
I took the jack apart after unstaking the bottom of the small diameter threaded shaft, removing the old L saddle and unstaking the top of the big threaded shaft. It then came apart easily.
There is a thrust ball bearing assembly consisting of two hard flat washers, qty 12 ball bearings and an inner and outer cage. These had rust and high wear on them, especially the cages. I sourced a high quality roller thrust washer assembly that will fit perfectly, and has a much higher load rating and should be smoother. I'll send pix to Larry when those come in, along with source and parts #s for the new bearings.
As far as grease, I recommend Donnelly MPG #2. It's a very high temp mineral
oil based grease with PTFE. It's clear, thick and won't melt off and drool in your trunk on hot days. Slippery as snot too.
After some thread repair, glass bead, painting and attachment of Acton's new proper saddle i will send pix to Larry to post as well.
Guys, I'd highly recommend disassembly, full inspection and bearing replacement on these old jacks found on Ebay, etc. Not worth risking your cars and health if not checked properly.