That's a really good question. I'm still repairing our 59 and not even sure if the Grover air pump is working yet. I would be hesitant to use a machine oul and contaiminate the water. One drop of normal air tool oil would taint a lot of water. I have some of the original paperwork on the watersystem and I don't recall reading what they advise to use. I wonder if something like KY would work?
Bet Andy of Inland RV would have some advice. If this is kept up top he will probably see it and respond.