For inexperienced DIYers; or any body not really comfortable with plumbing in general, the easiest option is to replace the whole faucet. While the faucet may be serviceable, stuck screws/bolts, proprietary disassembly steps, and difficulty finding replacement parts, make this a frustrating job for beginners.

The new faucet should come with instructions on how to install it, but here are the basic genérico steps to remove the old faucet and install the new one.

Removing the old faucet

Desligue a água

Look under the sink, and you'll (hopefully) see something like this.

Actually, you'll see two. One for the cold water, and one for the hot. Turn the knob until the valve is shut. Then turn the faucet on all the way, just to make sure the valves are fully closed.

If you do not have valves under the sink; or the valves do not stop the flow of water, you'll have to shut the water off using another valve down the line or the main shutoff valve.

Disconnect the supply lines

Attached to each of the shut off valves, there should be a mangueira como isso.

In some cases a rigid or flexible copper pipe will be used as a supply line, instead of a flexible braided supply line.

Usando um pipe wrench or tongue and groove pliers, disconnect these pipes from the valves.

Make sure you have a small bucket under the connection, to catch the water that comes out of the pipe. A small amount of water is normal, it's just the water that was left in the pipe between the shutoff and the faucet. If the water continues to flow or comes out under pressure, tighten the connection back up. This means the valve is not working or has not been fully shut off.

Remove the mounting nut(s)

If you follow the supply lines (the pipes you just disconnected) up, you'll find the tailpiece (a long threaded pipe) with the mounting nuts at the top against the underside of the sink. There may be two (one where each supply line connects), or just one in the middle depending on the faucet make and model.

A basin wrench makes removing these nuts much easier.

On some faucets, the supply lines are part of the faucet and cannot be disconnected. In this case the mounting nut may or may not be right at the end of the supply lines.

Once the nuts are removed and the supply lines are disconnected from the faucet (if applicable), the faucet should just lift away from the sink.

Clean up the mess

Once the faucet is removed, scrape any old plumbers putty from the top of the sink using a 1" putty knife

Install the new faucet

Now that you have the old faucet removed, it's time to install the new one. Follow the instructions included with the new faucet, or these generic steps.

Seat the faucet

Pegue alguns plumbers putty, and roll it into a "rope" (about 1/2" or so around) in your hands. place the putty rope either on the sink where the faucet will sit, or around the bottom of the faucet itself. The plumbers putty prevents any water that may be near the base of the faucet, from leaking down into the cabinet below the sink.

^{Do not use plumbers putty on natural stone (granite, marble, etc.) counter tops, use a bead of 100% silicone caulk instead.}

Carefully put the faucet in place, and press it straight down (don't worry if some of the putty squeezes out, that's normal). If the faucet does not stand on it's own, get a helper to hold it for you. Go back under the sink, and install and tighten the mounting nut(s) on to the tailpiece(s) using the basin wrench again.

Remove any excess putty that squeezes out from around the faucet base.

Connect Supply lines to the faucet

If the old supply lines are still in good condition, you can reuse them. Otherwise, head to the hardware store and pick up new ones (if not included with the new faucet). Make sure to take the old supply lines with you, so you get the right ones.

Using the basin wrench again, connect the supply lines to the threaded tailpiece(s) on the faucet.

Connect the supply lines to the supply

Connect the other end of the supply lines to the shutoff valves, making sure to connect the proper line to each shutoff (you don't want hot water coming out when you turn the faucet to cold).

Check for leaks

Slowly turn the shutoff valves back on, and watch carefully for any leakage. If you see a leak, turn the valve off and tighten the connection where the leak is.

Turn the faucet on (testing both hot and cold), and look for any leaks.

dicas

PTFE tape

Use PTFE thread seal tape on all threaded pipe connections, to reduce the chance of leaks.

Lube helps nuts come off

If any of the threaded connections are difficult to remove (when removing the old sink), soak the connection in penetrating oil.

The first step is to find out where the water is coming from. From what you described, it might be coming from the connections where your flexible supply line meets the faucet, or it could actually be from the base of the faucet which would indicate a failure somewhere in the faucet. Does it only leak when the tap is on? If so the leak is past the supply connection point.

Dry everything off. Now turn it on and using a flashlight under the sink, look to see if any water is coming from the connections. If not, look above the counter - is it definitely coming from the base?

This type of fixture is usually secured to the sink by 1 or more large bolts that apply squeeze to the underside of the counter. Start by turning off the water and removing these bolts to detach the fixture from your sink. See if you can pull it up enough to see the bottom of the faucet. Turn the water back on but leave the faucet off - see any leaks? Now make sure its dry and turn it on - try to see where the water is actually coming from.

If it is not coming from an easily serviceable part then you can either try to disassemble the faucet and repair it, or just replace it. If plumbing "isn't your thing" then replacing it might be the best bet because its really simple to do.

If you want to try and tackle the faucet itself then you need to find out how to disassemble it. If you are lucky you might find the manual for it, otherwise you'll need to look for clues as to how to take it apart. Often the handle comes off with a set screw that is recessed in the handle.

Disassemble it and visually inspect the components for worn washers, lots of mineral build-up, etc. When you find the culprit you now have to find a replacement part. Take it with you to a plumbing supply store to see if you can find a match.

It looks like a washer/seal needs to be replaced. Typically, you remove the handle to gain access to the cartridge, which you would replace.

Many manufactures have web sites that will try to help you determine what model you have by asking a series of questions like "one handle or two handle?". Here are links to Moen's e Delta's locais.

I would start by trying a few of these sites to see if you can find anything that matches.

As a last resort, you could remove the faucet completely and take it into a plumbing wholesaler where they should be able to determine what replacement cartridge you need.

I would buy a new faucet and new supply lines if the faucet does not come with enough hose to attach. You can get a reasonable priced one, or for a little more get one with a lifetime warrantly.

I am an amateur but it looks to me like it just needs an O ring and new plastic ring like the video below shows.

under kitchen sink diagram http://static.ddmcdn.com/gif/how-to-repair-a-spray-hose-1.jpg

looks like it needs an "O" ring and silicone grease. http://citykitchensseattle.com/tag/kitchen-faucets-leaking-at-base

I had no experience at all and replaced the whole toilet at my house and all the guts of a tank in two toilets. I guess I am mechanically inclined from birth.

Laura

That's a typical monobloc tap (faucet) with a C-shaped washer and a retaining nut. You can cheaply buy special long tubular wrenches specifically designed for this job.

Double ended - fits four different sizes.

The connecting hoses usually have a small thread at the tap end with a rubber o-ring. They can often be unscrewed by hand once the lower end is separated from the supply pipework.

Note the difference in setbacks of the hex portions to facilitate unscrewing in a cramped space.