Thanks for all the replies guys. I think I'm on the right track now. I really like the idea of drilling a hole and putting a cotter pin in it. We were talking at work today and wondering how you get the air out of the system or if it was even a problem. I was pointed towards Baum earlier today after making a few calls to other places. They have a nice website and I set up an account with them today, but haven't actually talked to them yet about the seals. I go through Omaha everyday to work so it'll be handy! Actually I'm going to look at another parts truck tomorrow with a steel dump box so I may not even use this box much. I know a guy who is interested in the grain box so at least I can pass along the info. The guy with the parts truck says it hasn't ran "for a few years" but ran "real good" when they parked it. Same motor and drive train as what I have so I may be trying to get it going tomorrow and bring 'er home. He wants about $500 for it but says the box is good so I figure it's probably worth that. The one I got from my Grandpas sale is pretty darn straight and between the two I may get something pretty nice going. I'll try to get some pics taken in case anyone wants to see how this goes.
Thanks again, Curt