I am replacing the sewer line under my basement floor due to some backflow and line condition problems. I took up the part of the floor where the line exits the front of my hosue to the street and the question is I have is related to the piece that actually runs under the foundation. My foundation is not on a footer but poured right on solid clay. The piece of clay tile that runs under foundation has the bell end about one foor inside the basement and the bell is shot, probably from some earlier repair work and some roots. So I was wondering if it's possible to pull that length out from under the foundation and get a section of new PVC line into the bell on the next piece of pipe?

I have a dual kitchen sink. When both sides are empty they drain fine. When one side is plugged, as when doing dishes, the empty side drains very slowly and expels bubbles as it slowly drains. When the plugged side is opened the slow drain takes off and drains normally. What's wrong?