I am doing some renovation in my basement and discovered my main drain cleanout was under cement. I figured I would break-away the cement while access is easy and before an emergency happens. In the process of removing the cement, i punched a hole in the 3.5'' brass cap. I tried my hardest to get the cap off by unscrewing it but had no success. I ended up busting the cap out with a chisel.
I went to home depot to buy a new cap. I only found brass ones and these galvanized test plugs with rubber gasket in the middle which may work. I purchased the brass plug for now.
The cast iron pipe threads are heavily corroded and I had a heck of a time getting the threads started on the new cap. I did get cap to screw on some but i think it is getting cross threaded. I have tried penetrating oil and lots of repetative tightening and loosening but i can only get it to make about 1.5 -2 complete turns before it gets too hard to turn.
Do you think this will be enough tension if my sewer backs up or should i look at buying a lead cap and possibly pounding it in? Does anyone have any other suggestions on what i can do or use in replacement of the brass cap? Would that test plug be sufficent (http://plumbing.hardwarestore.com/52...ug-115758.aspx