The unfortunate thing here is the galvanized pipe is level(no slope for
total drainage) and that is why it rusts out as sludge accumulates and
holds moisture there longer. Really, a plumber told me that bachelors
places are the worst as they are stingy with water, (so, with little
water use, it really never flushes out the pipes be they metal or
plastic and the pipes clog up) I know from experience that he spoke
the truth. It wood be nicer if you could turf the metal pipe for
plastic, but maybe it is not necessary yet . Unscrew the plastic from
the metal and have a peek inside. There will be rust and scum forsure.
Those are fairly thick pipes and it takes quite awhile to rust through
them, but looking at the picture again I see it is pretty easy to get a
wrench in there and unscrew it out, and go plastic.
wrote:
I recently purchased my first home. We decided that we would under
take some upgrading. When we stared on the bathroom we where planning
on just repainting. After further investigation we determined that the
drain pipe from the sink was corroded and leaking. We didn't like the
sink anyway so we pulled it out and hope to replace it with a pedestal
sink. When we removed the sink this what we found.

http://www.eganllc.com/images/pipes1.jpg
http://www.eganllc.com/images/pipes2.jpg

The end of the pipe that you can not see is into a cast iron pipe.

As you can see there are many issues. 1) Do I need to replace the
galvanized pipe? 2) Should I call a plumber to do this? 3) Can I just
shorten the coupling so that the drain is not over the water pipe?
(Shorten the coupling that is.)

Any help is appreciated.

Jonyskids