My house built in 1924 has a problem with the floor drain in the basement backing up occasionally. The floor drain is cast iron and makes such a radical U-bend that you can not get a snake through it. There is not a clean out in the basement either, at basement floor level.I have snaked the main line all the way to the street sewer lateral, and also snaked the kitchen lines to the main. The basement floor drain is at a lower elevation than the main drain line.. The floor drain is not used to discharge anything except air conditioner condensate.. I am looking for a simple cure relatively inexpensive. Do I just cut the concrete dig down, and put in a sump pit?

Why not do this the easy way and install a Flood-Guard (see image) and forget about those pesky backups. Check it out at: PlumbingSupply.com - Flood Guards For Floor Drains - check valves to prevent flooding (http://www.plumbingsupply.com/floodguard.html)
Good luck, Tom

Take a flashlight and look down that drain again. Many have a square nut type plug on the side that let you bypass that U. That's your trap BTW. How to Unclog a Drain Video ? 5min.com (http://www.5min.com/Video/How-to-Unclog-a-Drain-57208329)