Why do you want to replace the flange? If it is broken on the ends you can get a new repair ring to go around the broken pieces. If it is completely broken and is 4" piping you can get what is called a repair collar. This fits inside of the existing one and tightens up from the inside. If it is 3" pipe, you will have to break the concrete around it and dig it up. Then you will have to cut the pipe in the vertical and put a coupling and new flange on it.
Both existing flange rings(slide around the plastic flange body) are steel and badly rusted,I do not think spanner flanges will work...Toilet flange in the up stairs bath is positioned ~1' above plywood subfloor --Replacement toilet will probably will sit too high-I have recently gutted both bathrooms as this is a foreclosure remodel...
In the !st floor bathroom in oder to install a repair collar to 4' soil pipe how do I remove the old rusted flange..
All you have to remove is the outside collar. The part that fits around the pipe doesn't effect the repair collar as it fits into the hole of the old collar.