Replacing an old faucet with a new one can be pretty easy, but it can also turn into a giant headache if you don’t have the proper tools.  To make the job as easy as possible, it would be a good idea to have the following tools on hand.

Tools & Materials
2 Adjustable crescent wrenches 
Basin wrench 
Waterpump or groove joint pliers 
Socket wrench w/extender
Plumber's putty or silicon caulk
Teflon® tape
Flashlight
Towels
Faucet
2 Flexible Supply lines

Removing the old Faucet

Step 1
Shut off the water supply
There are usually two ways that you can shut off the water to the faucet. In most bathrooms the shut-off valves are found directly under the sink. Make sure to turn off both (hot and cold) water shut-off valves.  If your bathroom does not have shut-off valves under the sink, then turn off the main water-supply valve to your house, which is typically located in the basement. After shutting off the water, open up the faucet so that any excess water is allowed to drain out.  

Step 2
Disconnect the water supply lines
Use an adjustable wrench (or for difficult areas, a basin wrench) to disconnect the water supply lines from both the faucet tailpieces and the hot and cold water supply outlets. Drain any water left in the supply tubes into a bucket or large bowl.

Step 3
Remove old faucet from sink
Now that the water supply lines are disconnected, loosen and remove the lock nuts that hold down the faucet to the sink. If the nuts are rusted or corroded, spray them with penetrating oil such as WD-40 and allow the lubricant to seep into the threads before trying to remove the nuts.  Once the lock nuts are removed, lift out the old faucet.

Step 4
Clean the surface area where the new faucet will sit. Scrape away any residue that may have been left behind from the old faucet with a putty-knife and/or scouring pad. Then clean the area off with a 50-50 solution of vinegar and water and wipe dry with a clean rag.

Installing the new Faucet

When you are ready to connect your new faucet, flexible supply lines make connecting everything together that much easier because you don’t have to do any cutting in order to get the lines to connect. You will want to measure the distance between the new faucets tailpiece and the water supply valve outlet, so that when you go to buy new flexible supply tubes you will have an approximate length. The nice thing about the flexible supply lines is that they bend, so having a few extra inches is not a problem. For example, the new faucet I installed had a distance of 8 inches between the tailpiece and the water supply outlet connection. I ended up using 12 inch flexible supply lines, which fit into place without a problem. Lastly, you will also want to determine the nut size for each end of the water supply line.  In my case, it was 3/8’’ to value outlet on one end and 1/2” to faucet on the other, but they also come with 1/2” on both sides.

One challenge that I encountered when installing a new faucet was not having faucet connections soldered in place on the copper tubing. However, I was able to use a 3/8” x 1/2” compression fitting to make it work. I had mixed results using the compression fitting, I was able to get one side working leak free. However, the compression fitting on the cold water tube was leaking out of the top. I found out the hard way that once a compression fitting is on, it’s really on, and the only way to remove the compression ring from the copper tubing is by cutting the tubing square with a hack saw.  I installed a new ring and tested it for leaks and found out that it was still leaking out of the top. To be sure I wouldn’t get any leaks I ended up soldering the top of the compression fittings to the copper pipe. That did the trick.

Step 1
Connect the supply lines to the new faucet and tighten securely. Now set the faucet in the sink (However, don’t tighten the faucet down to the sink yet).

Step 2
Now connect the water lines to the valve outlet, and turn on the hot and cold water.  Look to see if there are any water leaks from the water line connections. If there are leaks you may have to tighten the connections more (or in my case I had to solder the top of the compression fitting ring to the copper pipe).

Step 3
Once you’ve determined that there are no leaks, it’s time to secure the faucet in place. If your new faucet has plastic or rubber on the base, just tighten the screws down by hand. If you do not have this then you will want to apply a bead of plumbers putty or silicon caulk around the bottom of the faucet. 

Step 4
Align the faucet so that it is positioned correctly and then tighten the mounting nuts with an adjustable wrench or a basin wrench (or in my case, a socket wrench). If you used plumber’s putty, wipe away any excess that may have squeezed out and is visible to the eye.

Step 5
Now install the lift rod, and connect it to the pop-up drain.

Turn on the faucet and double check to make sure you don’t have any leaks. If you don’t see any leaks and the pop-up drain is working correctly, you’re all done. Good job!