How To Replace A Leaking Cartridge Valve On A Two-Handled Monoblock Faucet

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Hiring a plumber to make repairs tends to be a common occurrence for most homeowners as the years pass. While it’s virtually impossible to completely avoid the need for a professional plumber’s services, there are some things you can do to minimize wear and tear on your plumbing system so it doesn’t succumb to the need for repairs often. Using low-flow aerators on your sink faucets and shower heads as well as insulating your exposed pipes before winter can make a big difference in your plumbing’s performance. On this website you’ll find many tips and tricks that can be used to keep your plumbing in good shape, and even to save yourself some money on water costs throughout the year.

How To Replace A Leaking Cartridge Valve On A Two-Handled Monoblock Faucet

14 March 2016
 Categories: , Articles


Two-handled monoblock faucets are trendy home plumbing appliances due to their modern styling and one-piece, integrated valves and body construction. However, like any other faucet, a monoblock faucet can develop a leak that requires prompt attention. Fortunately, repair of a leaky monoblock faucet is fairly straightforward and can be performed with a minimum of tools. Below is more information on how to correct a leak in your monoblock faucet:

Tools and materials needed

  • Replacement cartridge valve - Be sure to identify the correct cartridge valve for your particular faucet by examining a parts diagram or the faucet's installation manual. If you no longer have access to these documents, you will need to carry the defective valve into the hardware or plumbing supply store to match the part. In addition, it is important to keep in mind the hot water and cold water cartridge valves operate in reverse from one another, so be sure to buy the appropriate one for your needs.

  • Tongue-and-groove pliers - Sometimes known by the common trade name of "Channellock", these pliers can be easily-adjusted to provide maximum leverage.

  • Adjustable wrench - As with the tongue-and-groove pliers, this type of wrench is often called by its most-common brand name, "Crescent".

  • Hex key set - Depending on the location of manufacture, your faucet may need metric hex keys to fit, so have these plus a set of imperial-sized keys handy.

  • Screwdriver - An ordinary No. 2 Phillips head screwdriver should be sufficient for the task.

  • Shop towel or other small rag - Any type of cloth will do, as long as it is dry and you aren't concerned about rips or grease stains.

Step-by-step procedure

1. Turn off the fixture or main water valve - If you haven't yet turned off the water supply to your faucet, you will need to do so before starting the repair. Most bath and kitchen sinks have separate shut-off valves beneath the sink basin, so look there first. Turn the handle clockwise to turn off the water; some valves require you to turn the handle around several times, while others only require a 90-degree turn.

If your fixture does not have its own water valve, then you will need to locate the main water valve and shut off the supply. Main valves are often located in the front or back yards of homes next to the water meter and are covered for protection. You can turn the valve with a special "key" or use a pair of tongue-and-groove pliers. However, be extra cautious when turning off the main supply; too much force can break the valve and cause a massive leak.

2. Remove the faucet handle - On the side of the faucet where the leak is occurring, locate the hex set-screw that holds the handle in place. It may be under a decorative cap or on the back of the handle out of view. Pair up the appropriate hex key and turn the set-screw counterclockwise to loosen it. Be careful not to remove the screw entirely and risk losing it, but simply pull the handle off the stem as soon as it sufficiently loosens.

3. Remove the valve cover - Once the faucet handle is out of the way, you will view the stem extending from the cartridge valve; however, to remove it, you will need to take off its cover. Most covers simply unscrew from the monoblock, but you will need to use tongue-and-groove pliers to provide enough force. Before placing the pliers on the cover, however, be sure to cover it with a rag or cloth to protect the finish of the cover from scratches or gouges. Grasp the cover through the cloth and turn it counterclockwise to remove it from the faucet.

4. Remove the cartridge valve - After the cover has been unscrewed, the cartridge valve should be in full view. If the valve stem contains a brass screw, be sure to remove it and set it aside; you may need the screw for your replacement valve if it doesn't come with one.

To remove the valve, adjust the width of the jaws on your adjustable wrench until they snugly fit the cartridge nut. Turn the valve counterclockwise until it is free of the faucet body.

5. Install the new cartridge valve - Once the old valve is out of the way, screw the new cartridge into the monoblock faucet and tighten it with your adjustable wrench. Never over-tighten the cartridge, or you may strip the threads inside the faucet or on the cartridge. As mentioned earlier, if the stem does not contain a screw but has an empty threaded socket, insert the screw you removed in step 4; this is necessary on some faucets to maintain rigidity of the stem during operation.

6. Replace the valve cover and handle - Replace the valve cover by screwing it onto the faucet clockwise and use tongue-and-groove pliers to tighten the cover. Next, place the handle on the stem and tighten the set-screw to hold it in place.

7. Test the valve for leaks - After everything has been put back together, turn on the water supply to the faucet. Test the cartridge valve in its cycle between on and off to ensure there are no leaks. If any leaks appear, you may need to double-check your work to ensure the valve is tight and properly installed.

For more information, contact a plumber from a company like Allcounty Plumbing Heating & Air Conditioning.