Swapping out a bathroom sink

A handyman project to replace a broken sink with a new one



In New Jersey, mineral deposits are a perennial nuisance, slowly clogging valves and pipes and leading to drips. There is much work for plumbers, but this can get expensive. Many projects can be handled by do-it-yourself-ers as well as handymen. This picture essay shows one project involving replacement and installation of a new bathroom sink.

This is a public domain document. Feel free to copy text and pictures without attribution. It is a work-in-progress which I will try to improve over time. Like it? Add weblinks pointing to it. — tom sulcer april 2011

There was a slow drip, drip, drip leak in the upstairs bathroom sink. That’s the sound of money going bye-bye as we all know. The homeowners got tired of reaching under the cabinet to turn off the feeder valves. The faucet had rusted solid, with mineral deposits, making removal difficult. It didn’t make sense to install a new washer ring.

Underneath the cabinet, I turned off the hot and cold water supply valves. I disconnected one of the water feeder hoses using a wrench to get it going, then twisted it off by hand. It’s important to stabilize the rest of the pipe when applying wrench-pressure to a nut since there’s a risk of breaking off the pipe (and then you’ll have a gusher — I had that happen once!) The other hose nut didn’t budge. So I wonder if I can disconnect it up above later.

The G-shaped drain trap here unscrews easily by hand. Have paper towels or a cloth ready since there is still water (unclean) in the trap part. Consider wearing rubber gloves. I put it in a bucket to keep the mess under control. The area underneath a sink is crowded, sometimes difficult to get to. Removing the trap makes it easier to get underneath the sink.

Drain traps are bent in such a way so that water collects in the bottom. This traps sewer gases from escaping into our bathrooms. If a sink isn’t used for a month or so, the water in the trap evaporates, and you’ll smell something.

Getting underneath a sink can be tricky. Find something (old cushion? pillow?) to raise the bathroom floor surface a few inches so you’re flat with the inside of the undersink cabinet. I use folded tarps as a cushion to make it comfortable for my back. I maneuver underneath the sink. My LED flashlight lights up the innards. I use the special foot-long under-sink plumbing wrench to grab a nut and turn it. But no dice. It’s corroded solid. I apply 3-in-1 oil. No luck. I try tapping with a screwdriver. No change. Vise-grip wrench? Doesn’t work. I took a half hour trying to get the faucet off. I told the homeowner that I could try tapping with a hammer, but there was a good possibility that the sink would crack and we’d need a new one. The homeowner gives a green light.

See the green corrosion on the drain? The same corrosion was underneath the faucet. It was almost welded to the sink.

I tap the faucet.

Lightly with the hammer: tap, tap, tap, tap.

A little harder.

Still didn’t budge. Tap, tap, tap.

Then the sink cracked.

Surprisingly, from this point on, the whole job became easier. It required buying a new sink (about $68) so it was more costly in that regard, but the time-consuming nightmare of trying to gently dislodge the corroded faucet was gone. I bet an experienced plumber would have some trick or device to coax the faucet off gently, and spared the sink; but then plumbers cost a lot of money per hour. Getting a new sink simplifies the problem immensely. It is still a cost-effective solution for the homeowner.

I scrape lightly with a screwdriver between the rim of the sink and the counter-top. Glue and caulk come off, It loosens. I get the other feeder hose disconnected. I pull up the sink with the faucet & hoses — up-see-daisy. Here’s the old sink structure on the tarps on the floor:

I stuff a few napkins in the disconnected drain to the sewer to temporarily keep the smell out. I make a mental note to remove them before reconnecting pipes.

The homeowner had already purchased this new faucet. I lay out the pieces: the new faucet (left), the water stopper assembly (middle) and the drain (right):

Here’s the oval hole where the sink used to be.

All I need is a new sink. Off to the home center. You’ve heard the name. I put the old one in a cart.

An employee helps me find the same brand with similar dimensions. It’s $68. There’s a less expensive sink but it’s a different brand, and it might not fit exactly as well as pose other problems when pipes are lined up; last, the homeowner may not like the cheaper brand. The new sink will accommodate the already-purchased new faucet.

Last, I buy teflon pipe-threading tape. The white tape is spooled inside the blue ring. It costs about a dollar.

Assembling hoses and pipes underneath a sink is tough; so try to do as much assembling BEFORE you put in the new sink.

I work in the back of my van. The new sink is on the left, upside down; the old one is on the right. Those yellow boxes? Each one has a different type of tool. It makes it easier to find stuff.

I attach the new faucet first.

I turn the sink over gently. It’s porcelain, quite vulnerable to scratches and chips. I screw the washers holding the faucet down.

Next, I wrap teflon tape three times around the pipe threading. This helps prevent leaks.

Stems are ready for hoses.

Hoses are attached. I tighten these fairly firmly with a wrench. A general rule is when you’re connecting a metal pipe with a threaded metal nut, you can tighten fairly tightly; if it’s a plastic nut, be careful. I exert some force with the wrench, since I know the water will be under pressure. Some plastic nuts make a click-click-click sound when they’re in danger of being overtightened. If, when pressurized, hoses still drip, then I can tighten them further with the long wrench.

I attach the sink’s drain pipe (pointing up in picture; normally it will point down). It’s a plastic part with a black rubber washer (near bottom of photo). I don’t overtighten since it’s a plastic part. The ball-jointed metal bar (middle right) will let a user open and close the sink’s drain. The white ball (attached to the metal bar) goes inside the blue nut. When the metal bar goes up or down, the drain opens and shuts.

I assemble the sink drain valve. I figure out how to connect the long stem through the faucet to the drain opener beneath. The directions are sparse, but luckily it’s logical how the parts fit together. A metal clip holds the metal rod to the blue plastic adjustable stem.

I scrape old caulk off the top of the sink cabinet. I use my fingernails to avoid scratching the counter’s surface.

I caulk the underside of the sink. The idea is to keep counter water from getting underneath the sink. It’s not super necessary, but it’s just a precaution.

I gently place the new sink assembly into the opening, making sure it’s centered.

I look underneath. Looks good.

Top view. I push down gently on the sink. There are no clips underneath to hold it to the countertop. What holds it? Gravity. I add more caulk around the rim. It’s messy. I use my finger to smooth it. I run a wet towel to pick up excess caulk. It takes many passes.

Underneath the cabinet. Feeder hoses still have to be attached. I know the left one will be hot, the right one (mostly unseen behind the gray-blue drain) will be cold — I merely copy the old arrangement. Note how the napkin in the white sewer drain (lower middle slightly left) must be removed before re-attaching the drain pipes.

I scrape off the old teflon from the feeder pipes. Add new teflon. Attach the hoses and tighten with a wrench (holding the pipes so the wrench-action doesn’t break them). Here’s what it looks like:

I wash the white drain pipes with clean water in a slop sink in the basement. There was some junk in the pipes which came out. This way, there’s less risk of a clog in the foreseeable future. I remove the smell-preventing napkins. The drain pipes screw on. Since drain water isn’t pressurized, the risks of leaks are less; if a leak happens, it will probably be around the trap area, and is easily fixed.

Moment of truth.

I open the hot and cold water valves.

I hear water rushing!


But there’s a leak underneath the cabinet. It’s the connection between the bottom of the sink, and the drain pipe. I tighten it with another turn or two, and the leak stops. After several checks, everything is dry underneath. It works.

I wash my hands. I use rubbing alcohol soon thereafter. This kills germs. If you’re doing heavy-duty homeowner projects, it’s a good idea to make sure your tetanus shots are up-to-date (a booster shot is needed every 10 years.) I pick up the tarps, pick up my tools, it’s done. I tell the homeowner that if any trouble comes to this sink, I’ll fix it for free. I guarantee my work.

And that’s it!

My other handyman-related writings:

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