Every 5 years or so my main drain backs up due to roots in the pipe out to the street sewer line. Just had them cleaned out again.
M y problem is with the drain plug: it's leaking, the reason being that the threads on the plug are too worn/stripped to tighten it properly. This, in turn, seems to be caused by corroded/damaged threads in the old cast iron pipe which seem to be rounded off rather severely. They also seem to have built up quite an accumulation of rust and who-knows-what, essentially closing the size of the opening. (I purchased a new plug of the correct size but it won't even begin to go on due to the closing up of the original pipe hole diameter.
It seems to me that the threads in the clean-out access hole need to be re-tapped. Am I right? Is this possible and, if so, how does one do this?
Any help or alternate suggestions would be much appreciated.