Installing a new bathroom sink

Replacing a sink is really quite easy. Perhaps the most difficult part to deal with is the faucet. Its best to just replace the faucet when you replace the sink, as it isn't any less work to do both than just the sink.

Metal sinks are generally mounted with little screw clips like the one shown at left. Once you loosen them, they unhook from the sink, so that the sink can be lifted out.

The other thing to disconnect is the drain. If the trap on your sink is the type that can be detached, then its easiest to just take the whole trap off. This will make putting the new sink in easier. Not all traps come off though. if the trap has a little plug on the bottom that can be removed, its not the kind that comes off.

Either way, the stem from the drain on the sink is released by loosening the big plastic nut at the end of the drain pipe part, nearest to the sink's drain. This allows the sink's drain to be pulled out.

There's a funny little wedge shaped seal that will stick to the drain pipe, and cause the plastic nut from drain pipe to stick on the stem of the sink. Be sure to put the nut and wedge shaped seal on the new drain pipe in the same way. If the seal ends up getting wrecked, you can actually buy these seals new where you buy plumbing parts.

With the sink removed, its time to clean the crud from around the edge.

I was replacing the sink with a porcelain sink. There were no clips that go on the bottom of the sink. The only thing to hold it in place is gravity, and caulking.

I used caulking from a tube. Its harder to get a nice bead from a tube than a caulking gun. But I used caulking from a tube, because the rest of a cylinder of caulking in a caulking gun will start to go solid once the tube is opened, and I didn't need a whole caulking gun tube's worth.

With the bead of caulking on the sink, I carefully then lowered it over the hole, making sure that its centered right.

Next its time to install the drain. The drain typically clamps itself between the top and bottom. On the bottom side, ther's a wide conical rubber gasket that presses against the sink, with a brass washer behind it, and a nut to tighten it. I put caulking all around the rubber gasket just to be on the safe side.

It helps to have a helper for this part - somebody to hold the drain in from the bottom while screwing in the flange from the top.

The instructions say to seal it at the top with putty, though caulking will do the job too. Its important to seal around the part that goes in on top, so that if you close the drain plug, the water stays in the sink instead of leaking around this part.

The part that goes on the bottom of the sink should have a rubber seal, though, to be safe, I put some caulking on that as well before I installed it.

Once the top part is screwed on as far as it will go, its time to grab a pipe wrench and tighten the nut from the bottom to pull it all together and put some pressure on that rubber gasket on the bottom.

Be sure to dry fit everything first before you assemble it with caulking. Caulking is really messy once you get it on your fingers. Its best to have a roll of paper towel handy to wipe your fingers with when you work with caulking, otherwise you inevitably get it on everything, including your clothing. And caulking doesn't wash out! The saving grace of caulking is that it does stay soft, and you can scrape it off if need be even after it has solidified, unlike putty.

Its a good idea to install the drain plug mechanism before installing the trap. Or at least I realized that because when I did it, I ended up accidentally dropping the plug part all the way down into the trap, and had to undo it again just to get it back out. Getting that rod that sticks out to the right to go through a hole in the drain plug, and putting it all together is surprisingly fiddly. I couldn't put that part in before installing the drain mechanism, because it would have gotten in the way a little when installing the flange on the top. But really, that's more part of installing the faucet

The bottom of the drain spout always seals to the drain plumbing using one of these clever conical, or wedge type of gaskets. The nut on top pushes the wedge into the drain pipe, which compresses it and cause it to perfectly seal between the drain plumbing and the spout from the sink.

And the sink all done and installed, with new faucets. Looks much better than the old one.