Tried cleaning all pieces. Made rope of plumbers putty, slipped it under flange and then tightened down. Looks like most of putty oozed out. water does not drip from under sink, it just runs into drain.
The space between the flange and the sink seating area is quite small. If it is not leaking, the putty job was successful. The idea behind making a rope from the putty is to assure a complete seal. Silicone works, but makes disassembly much more difficult.
Most of the putty is supposed to ooze out, with just a little remaining taking up the space between the drain pipe and the sink. If no water is dripping under the sink, then the water is draining into the pipe. The mechanical stoppers are notorious for going bad after a while. Their seals dry out and crack, or their mechanism does not apply enough pressure to prevent drainage. They are also difficult to replace. They can be replaced with manual stoppers of different styles that do not activate from using the push/pull behind the knobs. It is not the drain seal between the drain pipe and the sink. It is the stopper that is failing you.
I have used teflon tape with success in sealing threads on home projects. I have also used clear, silicone adhesive, Goop with good results. Plumber's putty was originally designed for cast iron fittings and not brass or pvc pipe fittings. Teflon tape comes in different colors where each applies to a specific type hook-up; liquid and gas. So, check the label before purchasing.
plumbers putty is used around the top piece that you see in your sink it goes under that and no where else if you have a leak some where else if it is on a threaded portion of pipe use teflon tape
