How to unscrew the locknut underneath a tap (faucet).

In this guide, we are going to show you how to unscrew the locknut on a faucet / tap.

This locknut can be extremely difficult to loosen. This is due to three factors.

  1. It is located in an awkward area underneath the basin.
  2. The pipes that feed into the faucet will often “crowd it” and prevent you from being able to get a proper grip on it.
  3. The long threaded bar that it screws onto will stop you from using a regular socket wrench.

If you attempt to loosen this locknut using a regular spanner, you will find that it is a frustrating experience.

This is the kind of job that can test the patience of a saint.

unscrew locknut on faucet

In the image above, you can see the locknut in question. It screws onto a long threaded bar.

You can also see that the pipes are extremely close to it.

Other websites will tell you to use a basin wrench for this job. However, that will not work in this case. A basin wrench is too big and it will not have enough room to grip onto it.

Use a back nut spanners.

In this case, the best tool to use is a back nut spanners.

backnut spanners

Mono tap back nut spanners.

This tool will pass through the threaded bar until it finally reaches the nut. At that point, you can simply turn the spanner and unscrew it.

The pieces underneath a tap can become rusty over time.

Note that in certain cases, the nut and bar will be rusty and covered in limescale. As a result, it may break off as soon as you apply any pressure.

rusty locknut on a tap

Rusty pieces from a 15-year-old faucet. This rust is due to small amounts of water trickling down onto them over the years.

In the image above, you can see that the threaded bar has become worn at the top. This caused it to break off.

If the nut refuses to budge, you can try to tap it with a hammer. This can help to loosen it.

You can also try to tighten it and then loosen it again – going back and forth until it finally starts to move.

You can try to unscrew the locknut on your faucet using a needle nose pliers.

Another alternative is to try and use a needle nose pliers. You will find various sizes of these at your local hardware store.

needle nose pliers

These pliers have a thinner nose.

Although needle nose pliers are thin enough to get a grip on the nut, they are still more difficult to use than the back nut spanners.

In other words, it might work, but you will probably end up shouting a few swear words before the job is complete.