Hello,

My kitchen sink drain pipe leaks where the black U-shaped (p-trap?) screws onto the straight pipe from the sink. I've read that there is supposed to be a plastic ring or fitting that goes between the two pipes inside, and then plumbers tape on the threads where it screws together. Is that correct, and how exactly do I make sure it goes together correctly? There are several projects such as this where I'm getting a house ready for sale, and doing the work myself, so I'll be asking questions often. Thanks in advance for any help and advice :)

Since you said it was black pipe it must be ABS pipe. You described right the way it is put together with a smaller pipe slipping into a larger pipe with just very little clearance. That is what the plastic ring is for to fill that space and to seal the two together enough that it will not leak. The bottom of the trap or the J-bend is what it is called has the threads on it and the Piece coming down from the sink is called a tail piece. It has no threads and it is the one that slips into the J-bend. You slip the plastic nut up on the tail piece and then you slip the washer onto the tail piece after the plqastic nut. The washer is made in a bevel shape and is flat on one side. The flat part goes onto the tail piece so that it will be up towards the sink. You then slip the J-bend into place and start to plastic nut the nut, it should turn several rounds with no problem. If it turns one or maybe two rounds it is possible you have it cross threaded so unscrew it and start over making sure that the nut goes on straight. Use the little wings or the knobby parts of the nut to tighten it with your hand. Tighten is as tight as you can with you hand and that is all that it need to be tightened. You don't need any plumbers tape (teflon tape) on the threads.

Thank you Letmetellu. The black pipe is plastic, is that still called ABS?:cool: