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How to Loosen Brass Fittings that Are Stuck

Brass fitting on a plumbing line

At one time or another, plumbers and contractors have to work on seized fittings, and that can be a challenge. In this article, we show you how to loosen brass fittings that are stuck and difficult to unscrew. We’ll also see the things that could cause fittings to stick, if brass fittings can be over tightened, and how to avoid doing so.

Stuck Brass Fittings

Stuck brass fittings are brass fittings that you cannot easily remove from their adjoined pieces. Normally, the fittings are easy to take apart with only a wrench and some little effort. When stuck, they may require more than wrench to remove.

Stuck brass fittings can be those that are seized to valves, or fittings that are tightly bound to pipes and other installations. And while you could easily cut into them, doing so is not always a viable option.

This is especially when carrying out repairs and you want to re-use a fitting, or if cutting the fitting could end up damaging other parts of the installation. In such situations, you want to safely loosen and remove the seized fitting.

Stuck Brass Fittings Causes

Several factors can lead to stuck brass fittings. These vary from thread damage and material buildup (caused by age), to over tightening. Here, we are focusing on threaded fitting types, as these are among the most common. More about the causes of stuck fittings below:

  • Old Brass Fittings: After a long time and depending on the type of brass used, increased levels of internal deposits may cause thread to bind. This is one of the most common reasons for old brass fittings sticking.
  • Damages Thread: apart from age, brass fitting thread can get damaged, sometimes during installation and either from improper connection steps or not using a sealant. This could lead to the fitting sticking.
  • Over-tightening: when over-tightened, brass fittings risk getting their threading damaged. That could cause them to seize and become difficult to remove later on.
How to loosen brass fittings that are stuck
How to loosen brass fittings that are stuck

How to Loosen Brass Fittings That are Stuck

After an overview of what causes them to bind, let’s now look at how to loosen brass fittings that are stuck. Several techniques are available; using a wrench and pliers, using penetrating oil or fluid, and by heating the joint.

Important! Before you can begin loosening stuck fittings, cut off supply to the line you’re working on. Ensure too, that water or other media is completely removed from the line.

How to Loosen Brass Fittings with Penetrating Oil

Penetrating fluid is a type of oil that can lubricate thread and loosen corrosion or other deposit. You can effectively use it to loosen old fittings and make them easier to remove.

Have with you these tools and supplies: penetrating oil, adjustable wrench, and a clean rag. These steps explain how to loosen old brass fittings using penetrating fluid.

  • Using a clean rag, wipe the fitting. This is to remove any dirt or dust.
  • Spray a generous amount of penetrating fluid onto the fitting joint and locknut.
  • Allow it to soak for about 10 minutes (depending on the fitting’s condition, this may take longer).
  • Once soaked, wipe the fitting with the rag to remove excess fluid.
  • Using an adjustable wrench, turn the locknut in a clockwise direction.
  • The fitting should now be easy to unscrew.

How to Loosen Brass Fittings by Heating

You can also loosen a fitting by heating the seized section. The heat will break down or soften the sealing compound or other material and release the thread.

For this, you’ll need the following: a clean rag, a propane torch, a heat shield, and adjustable wrench. When loosening brass fittings with a propane torch, ensure that you have a fire extinguisher on standby.

  • Wipe the brass fitting to clean it of dust and debris.
  • Place a heat shield or fireproof cloth behind the fitting. This is to prevent the heating flame from starting a fire or burning anything.
  • Using a propane torch (or you can use a heat gun), direct the flame at the fitting.
  • Do not heat the stuck fitting on one spot to avoid causing damaging. Instead, constantly move the flame back and forth
  • After heating for some time and with the wrench positioned over the lock nut, attempt turn the nut in a clockwise direction. The nut should be easy to turn.
  • If the fitting didn’t loosen, consider repeating the steps.
Tightening brass fitting with a wrench
Tightening brass fitting with a wrench

Can You Over Tighten Brass Fittings?

You can. This is one of the reasons for stuck brass fittings. So it’s recommended that plumbers and contractors ensure they’re tightening these fittings to the correct torque. So, how do you tighten brass fittings correctly without overdoing it?

While there’s no recommended torque when tightening brass fittings (situations are different), a few rules and tips can ensure that you do not under or over tighten your fittings. Here’s what to know.

  • You’ll want your brass fittings more than hand-tight, but not too tight as to damage the thread.
  • Since brass is a malleable material, it’s recommended to only tighten brass fittings with 1 or 2 turns after hand-tightening them most of the time.
  • Alternatively, you may want to consider tightening your brass fittings until you feel the torque is just right. This is usually when the turning suddenly stops.
  • Note that using Teflon tape lubricates the thread and that may entice you to over tighten a fitting. Always take caution when you’ve applied the tape to seal your fittings.


With brass fittings being so common, it helps to know how loosen brass fittings that are stuck and not easy to take apart. This can involve the use of only a wrench, penetrating fluid, or the help of a propane torch. Depending how much stuck they are, you may want to use the most effective method on your fitting, which heating the joint with a propane torch.

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