How to Replace a Leaky Toilet Water Shutoff Valve

By |Last updated on |Bathroom, Toilets|12 Comments

This project explains how to replace a leaky toilet water shutoff valve by removing old valve and install a quality Brasscraft G2 Series 1/4 Turn Ball Stop Valve.

How to Replace a Leaky Toilet Water Shutoff Valve

I could have repaired the old multi-turn water shutoff valve by replacing bonnet packing washer by purchasing a repair kit for around $2, however the new 1/4 turn stop valve only costs about $8 at Home Depot and it’s almost the same amount of work to fix an old valve compared to installing a new valve. The new Brasscraft 1/4 Turn Ball Stop Valve model G2CR14 C1 has a 1/2 inch compression inlet and 3/8 inch compression outlet that fits 1/2 inch copper water pipe:

Brasscraft 1/4 Turn Straight Stop Valve #G2CR14 C1

Brasscraft 1/4 Turn Straight Stop Valve #G2CR14 C1

Water stop valves are also installed on the hot & cold sink faucet pipes. Your stop valve might be an angle stop if the water pipes come out the wall instead of the floor, meaning the 3/8 inch outlet is at 90 degrees to the inlet (i.e. an elbow). The installation steps are the same for both straight and angle stop valves.

I prefer the 1/4 ball stop valve because in my opinion it’s a better design than the multi-turn stop valve for the following reasons:

  • Only 1/4 turn to open or close the valve – a nice convenience.
  • The ball design positively shuts off the flow of water when closed, and does not obstruct the flow when open.
    Compare to the multi-turn stop valve, which is type of globe valve.
  • Less prone to leakage over due to the ball design and two internal o-rings on the valve stem.
  • More durable and reliable.

The Brasscraft G2 series 1/4 turn ball stop valve operation is illustrated in the following sequence, from fully open (left image) to fully closed (right image):

Brasscraft 1/4 Turn Straight Ball Stop Valve Operation

Brasscraft 1/4 Turn Straight Ball Stop Valve Operation

Toilet Stop Valve Compression Fittings

The Brasscraft 1/4 turn stop valve uses compression fittings that consist of a brass sleeve that fits over the 1/2 inch copper tube and 3/8 inch toilet or faucet connector hose (see photo below). The compression nut squeezes the brass sleeve against the tube for a water tight seal. The advantage of compression fittings over sweat (i.e. heat soldered) connections are:

  • Requires only basic skills to install, versus the practice needed to learn how to solder a sweat joint with a propane torch.
  • No heating with a torch means less chance of overheating the valve body and damaging the plastic & rubber components when soldering a sweat joint.
  • Can be installed in cramped spaces where a propane torch would be a fire hazard.
  • (Usually) easy to remove with only a wrench if the valve needs replacement.
  • Can be installed “wet”, meaning the copper pipe doesn’t not have to be completely dry.
    A sweat fitting by contrast can only be soldered when the pipe is dry because any water inside the pipe will absorb heat from the propane torch creating relatively “cold” spots – it only takes a few drops of water to be a problem! The melted solder won’t completely wick into joint with cold spots leaving gaps that will leak. Residual water inside the pipe is often a challenge because you’ll stick a rag in the pipe to soak up the water, only to find a small trickle re-wetting the inside of the pipe due to water backflowing from pipes elsewhere in the house.

I also have installed solder sweat joint stop valves on new plumbing installs when there’s sufficiently long copper pipe stubs to use a propane torch. A sweat joint will practically last forever.

Brasscraft 1/4 Turn Straight Ball Stop Valve: Compression Nuts & Sleeves

Brasscraft 1/4 Turn Straight Ball Stop Valve: Compression Nuts & Sleeves

The following tools are needed to replace a water shutoff valve:

  • Flat steel file to deburr the inside of the 1/2 inch copper tube; and to bevel the outside edge of the tube.
    The end of the copper tube may have a slight ridge made by the cutting wheel of the tube cutter that can make it difficult to insert into the stop valve body. A quick filing will knock down the ridge; just spin the end of the copper tube against the flat file while holding it at an angle. If replacing a stop valve, you won’t need the steel file because deburring and filing have already been taken care of.
  • 4-in-1 Brush for cleaning 1/2 inch and 3/4 inch copper tubing.

Aside: Small diameter copper pipe is more correctly described as “tubing”.

Water Stop Valve Installation: Valve Assembly and Tools

Water Stop Valve Installation: Valve Assembly and Tools

Water Shutoff Valve Compression Fittings

Before replacing the toilet stop valve, let’s take a look at how it installs on 1/2 inch copper pipe.

The water stop valve compression fitting installation steps are:

  1. Clean the end of the copper tubing with the Oatey 4-in-1 brush. Insert the tube into the brush hole and turn the brush. The brush wires will remove any paint, dirt and oxidation from the outside of the copper tube.
  2. Slide the compression nut over the tube with the threads facing the end of the tube (i.e. facing the stop valve).
  3. Slip the brass compression sleeve on the tube about an inch or so. You don’t need to be precise here.

The copper tube will go about 1/2 inch into the stop valve body as indicated in the following photo:

Water Stop Valve Installation: Compression Fitting Brass Sleeve and Nut

Water Stop Valve Installation: Compression Fitting Brass Sleeve and Nut

Slide the stop valve onto the end of the copper pipe until it’s fully seated. The valve body should go on easily. You can see how the brass compression sleeve is beveled on both ends and will be squeezed against against the valve body and copper tube to make a water tight seal:

Water Shutoff Valve Installation: Compression Fitting on 1/2 inch Copper Pipe

Water Shutoff Valve Installation: Compression Fitting on 1/2 inch Copper Pipe

While holding the valve body against the end of the copper pipe, press the compression nut and brass sleeve up to the valve body. Spin the nut on by hand, then tighten the nut with a wrench until you feel it seat (or bite) against the brass sleeve – it’s a distinctive feel, you can’t miss it – then tighten the nut an extra 1/2 turn. Take care not to over tighten the nut because you can crack the valve or nut. You can always tighten the nut a bit more if it leaks.

Install a Water Stop Valve: Compression Nut and Valve

Install a Water Stop Valve: Compression Nut and Valve

The water shutoff valve compression fitting system is a simple and reliable system.

This project is continued in How to Replace a Leaky Toilet Water Shutoff Valve – Part 2.

Take care,

Bob Jackson

Copyright © 2018   Reproduction strictly prohibited.


  1. jack andrews January 5, 2015 at 5:54 pm - Reply

    Superior presentation. Precisely illustrated.

  2. Kevin Ross November 7, 2015 at 6:21 pm - Reply

    This is your second article I’ve read. Wonderfully well written (and hyperlinked and photographed)! How-tos are rife on the ‘net but most are poor, even among those that are not “google bait” SEO bullshit. I’m in information design / IA and will use this as an examplar of excellence of its kind.

    • Bob Jackson November 8, 2015 at 10:25 am - Reply

      I author projects to my personal standards with an emphasis on quality and detail. I’m pleased you noticed.

  3. jim doyle March 11, 2016 at 12:42 pm - Reply

    bob the presentation is very complete and beautifully illustrated

  4. jim doyle March 11, 2016 at 1:05 pm - Reply

    i do have a related question i am replacing a toilet stop valve. the current set up is a 1/2 in copper pipe with a brass fitting swetted on which has threads and is screwed into a BrassCraft valve multiple turn shut off 1/2 by 3/8 outlet. because the fitting is so close to the wall, i am hesitant to try and sweat it off. will a threaded {if available} new valve provide a leakproof solution if i use teflon tape the threads? thanks so much
    jim doyle

  5. Stephen January 14, 2017 at 5:37 pm - Reply

    Hi Bob,

    I just read this article after discovering that my kitchen faucet shut-off valves don’t shut off all the way. I am very impressed with your level of detail and your skill in presenting things clearly and concisely, and I want to thank you for taking the time to share your expertise with the world (and free, I might add!).

    I also have one question that may be of interest to future readers: The brass compression sleeve “bites” into the copper, which deforms it slightly. When replacing one of these fittings, is it necessary to cut off of the area where the old sleeve “bit” into the copper pipe? Or, can the pipe simply be re-used without any further work (assuming the previous installer cut and filed it properly)?

    Apologies if this is answered somewhere else.

    Best Regards,

    • Bob Jackson January 14, 2017 at 9:03 pm - Reply

      No worry, the soft brass compression sleeve will make a watertight seal even if there’s a “bite mark” or ring where the end of the old sleeve met the compression nut. Clean and polish the copper pipe before installing. The new brass sleeve with either settle into the old bite mark or make a new one. I’ve replace water stop valves many times without leaks.

  6. Stephen January 14, 2017 at 11:25 pm - Reply

    Hi Bob,

    Thank you! I thought that would be the answer, since copper is so soft, but I figured it’d be best to hear the answer from an experienced pro.

    Thank you again for your time.

    God bless,

  7. Gary W. Goodwin June 16, 2017 at 4:44 pm - Reply

    In my limited experience, once a compression fitting is seated, the compression ring and copper pipe underneath become permanently constricted slightly, making it difficult or impossible to remove the ring, as well as the associated compression nut, without cutting off the end of the copper pipe

    Gary G.

  8. David Landy July 29, 2018 at 11:37 pm - Reply

    I have heard conflicting comments about removing the old compression ring, and those that say you can’t – so leave it on and use it with the new shut off valve (keeping the old nut also)….

    There are tools to remove the old, seated compression ring – this sounds like it would be hard to do and at best leave the copper pipe in a damaged state….

    Leave the old compression ring ?
    Replace the old compression ring with the new one included with the shut off valve ?

    • Bob Jackson July 30, 2018 at 6:43 am - Reply

      Compression rings are a one-time use item because the soft brass brushes and deforms. I’m aware of compression ring removal tools and asked the Master Plumber who replaced my water heater about it. He’s unaware of any plumbers using one, which speaks volumes.

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