My parents have a leak in their cast iron sewer line. Unfortantely the previous owner poured a 12″ wide by 18″ high by 6′ long knee wall in the basement at a right angle to the exterior wall. As you can guess, the leak in the cast iron pipe is embedded in the concrete. It is leaking about 6″ from the exterior wall in the concrete and onto the basement floor. I have to figure out someway to remove the block of concrete and not bust up the cast iron were it exits the house. I can put a sleeve over the cast iron pipe and connect it to a new PVC service. Anyone have any brilliant ideas on how to remove the concrete from around the pipe without busting the pipe. This was put in back in the 20’s or 30’s. Thanks for your help.