First let me thank all for the past advice I have received on this forum. I have a 54 NAA. I have an owner's manual and Master Parts manual. These don't cover everything I would like to do. Any suggestions for the best books for information to restore this tractor? It is in pretty bad shape, but does run. Secondly, the owner's manual states there is an oil fill nut for the steering (ball bearing and worm gear). How do I check the oil in there and can I drain and replace it? If so, what type oil would I use?