Kohler Forte Faucet Troubleshooting & Repair Guide

This Kohler Forte Faucet Troubleshooting & Repair Guide will give you easy to follow steps for troubleshooting and repairing Kohler Forte kitchen and lavatory faucets. If you are having problems with a Kohler Forte in most cases following these easy steps and replacing a few inexpensive parts can restore the faucet to operating like new again.

The Kohler Forte Faucets follow the same troubleshooting logic as any other faucet regardless of where they are located or, the number of handles with minor additional steps. If the faucet is not shutting off and continues dripping or, running with a steady stream the problem is almost always a cartridge that requires replacement. If you turn on the faucet and water comes out at a reduced flow or, not at all in most cases you will find the aerator on the end of the spout has clogged with debris and the flow is blocked, you can unscrew it and either clean or, replace the aerator. On kitchen faucets with a side spray that are not flowing you should check the aerator first for debris and if that does not fix the problem, check the side spray to see if it has flow while the spout doesn’t, which will indicate a problem with the diverter sticking. The diverter sticking can also be indicated by water coming out of both the spout and side spray at the same time. In some cases there may be other blockages an the supply lines or, valves coming to the faucet but in most cases you should start at the faucet as it is the easiest place to start checking.

Once you have figured out what parts are malfunctioning and require replacement you are ready to go to the next step of disassembling the faucet and replacing the parts. Before rushing in blindly it is probably a good idea to get a look at the service parts diagram for your faucet to get a picture of how the parts go together. This will help you to get an idea of how to take it apart and put it together again, along with being able to see what parts you will need to purchase and in some cases where only one part is used you can purchase them in advance. Other cases where 2 different parts are used you will have to disassemble to find out what is used on your faucet the buy the parts.

Kohler Forte Single Handle Kitchen Sink Faucets

The Kohler Forte Single Handle Kitchen Sink Faucets are all very similar and the same parts, disassembly and reassembly procedures for cartridge replacement apply to all of the models, which include model numbers K-10411, K-10412, K-10413, K-10414, K-10415, K-10416, K-10430, & K-10433. Turn off the water supply to the faucet, in most cases there are stop valves under the sink that should accomplish this. You should verify the water is off before proceeding with the cartridge replacement by turning the faucet on to both hot and cold to check. Remove the plastic plug button from the rear of the handle and loosen the allen set screw allowing the handle to pull off. Remove the bonnet cover then using an adjustable wrench remove the bonnet nut. Once the bonnet nut is removed you are then able to grip the cartridge and pull it up out of the valve body. You will need a Kohler # GP1016516 replacement cartridge and the new one should be lubricated with some plumbers grease and put back into position with a assembly in the reverse. If there is a problem with the diverter you will need to get deeper into disassembly with the diverter located under the spout. All Kohler single handle side spray faucets use the Kohler # 75878 diverter but you should check the diagram for your faucet as additional parts such as O-Rings will probably be needed when you remove the spout. The K-10433 pull out style faucet does not have a diverter under the spout but does have other components such as a check valve, and screen where the hose connects to the pull out head which should be checked when there are flow problems. Once reassembled turn the water back on and check for proper operation and leaks.

Kohler Forte 2-Handle Wide Spread Kitchen Sink Faucet

The Kohler Forte 2-Handle Wide Spread Kitchen Sink Faucet # K-10445 cartridge replacement is accomplished turning off the water supply usually with valves under the sink, then you need to unscrew the bonnet at the base of the handle. This will unscrew and the handle assembly will come off with it. Sometimes these can be difficult to remove especially if they have been wet and have gotten corroded, a strap wrench may help in unscrewing the bonnet. On the K-10445 faucet 2 different cartridges are used and you will only be able to tell which you have after the bonnet is removed. One has a cartridge made of metal in which case a Kohler #GP77005 (hot) & GP77006 (hot) are used, and the other cartridge is made of plastic in which case a Kohler #GP1092204 (hot) & GP1092203 (cold) are used. After the bonnet has been removed us an adjustable wrench to unscrew the hot and cold cartridges or, valves and grease the new ones with plumbers grease and reassemble. Make sure that the right cartridges are on the right side or the faucet handles will work backwards. Also apply plenty of grease to the bonnet before screwing it back in place to make removal later should another cartridge need changing easier. This faucet also uses the Kohler # 75878 diverter but you should check the diagram for the faucet, as additional parts such as O-Rings will probably be needed when you remove the spout and replace the diverter. Turn the water supply back on test for function and leaks.

Kohler Forte Single Handle Lavatory Faucets

The Kohler Forte Single Handle Lavatory Faucets K-10215-4 & K10217-4 disassemble and reassemble the same as the Kohler Forte single handle kitchen faucets except they use a Kohler # GP1017426 cartridge, and they do not have a diverter or movable spout.

Kohler Forte Wide Spread Two Handle Lavatory Faucets

The Kohler Forte Wide Spread Two Handle Lavatory Faucets K-10272-4 &10272-4A disassemble and reassemble the same as the Kohler Forte two handle wide spread kitchen faucets and use the same two different cartridges Kohler #GP77005 (hot) & GP77006 (hot) or, Kohler #GP1092204 (hot) & GP1092203 (cold). However lavatory faucets do not have a diverter or movable spout.

Kohler Forte Two Handle Centerset Lavatory Faucet

The Kohler Forte Two Handle Centerset Lavatory Faucets K-10270-4 & K10270-4A can be repaired by shutting off the water supply valves usually found under the sink, then they have a ring below the handle, which unscrews for the handle to be removed. Once the handle is removed an adjustable wrench can be used to remove the hot and cold cartridges from the valve body. Only Kohler # GP77005 (hot) & GP77006 (cold) cartridges are used. As always grease the cartridge with plumbers grease and the retaining ring for the handle to assure easy disassembly in the future.

As you can see with a few basic tools and a few parts, in many cases you can easily fix a Kohler Forte Faucet.

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62 comments on “Kohler Forte Faucet Troubleshooting & Repair Guide
  1. joe says:

    I have a Kohler bathroom sink and I’m trying to replace the cartridges on the hot and cold handles. I’ve been trying all day to replace the cartridges, but I just cant seem to get them out. I’m afraid if I pull on them too hard I’m gonna break the entire sink. Am I supposed to replace the cartridges by going underneath the sink to loosen a screw or something? I’m at my wits end. I believe the model number for the cartridges are GP77006 and GP77005. thanks for any help

    • Redwood says:

      Hi Joe,
      The Kohler GP77006 and GP77005 are ceramic cartridges or, stems that unscrews from the faucet body.
      After removing the handle you should see the nut which you will need to turn to unscrew the cartridge.

      Kohler GP77005/GP77006 Ceramic Cartridge

      This is all done from the top, there is nothing to be done under the sink and the sink should not ever be in danger of being broken.

  2. emil says:

    How do you remove the mineral deposit to loosen the nut on the stem

    • Redwood says:

      Hi Emil,
      You can try white vinegar to dissolve the minerals then something like PB Blaster or, AeroKroil to penetrate into the threads. If the leak has been happening for a while it can be tough to get the nut loosened.

  3. Larry says:

    I have a 5yr old K10433 pull-out kitchen faucet. The trouble is the spout being difficult to rotate which would seem to be solved by replacing the 1038326 bearing and 42043 o-ring. I have not gotten that far because I am unable to budge the 1003662 bonnet. Attempts to loosen the bonnet threaten to twist the whole stem in its mount to the sink. Any suggestion on loosening the stuck bonnet? I think the bonnet is a plastic part so have not tried any penetrating oils. Thanks.

    Update from Larry 2014/02/21 at 10:43 am: I spoke with Kohler customer service this morning and they suggested the white vinegar to dissolve the mineral deposits. They’re also sending the bearing kit. Excellent customer service!! I’ll leave the vinegar on until the parts arrive.

    • Redwood says:

      Hi Larry,
      The bearing kit should solve your problem with the stiff movement of the spout. Sorry I didn’t get back to you sooner but the vinegar soak should dissolve any buildup of minerals making the bonnet hard to remove, it doesn’t take very long either. In some cases the bonnet nut may have to be destroyed to get it removed. I’d suggest that when you reinstall the bonnet nut that you use a liberal application of plumbers grease on the threads so that future replacement of the bearing kit or, cartridge is easier. Hopefully you get your parts quickly and still have praise of Kohler’s customer service, my personal experience with them has been numerous back orders and long waits for parts, sometimes as long as 3-4 weeks which is a pain with customers wondering when I’ll fix their product. If removal of the bonnet nut is going to be destructive I’d suggest obtaining a new cartridge and bonnet nut before proceeding.

      Hope this helps,

  4. alvin says:

    Installed new Kohler kitchen tap and connected the proper water lines up but no hot water is coming out of tap.

    • Redwood says:

      Hi Alvin,
      Since there is no hot water, but you have cold water, it isolates the problem quite a bit. I’d suspect that either a gate valve was used and it is broken so it doesn’t open or, some debris was dislodged while you were working, and has moved to a position where the waterway is blocked which is not uncommon at all.

      I’d start with closing the valve and disconnecting the supply line from the valve, then with a container under the valve to catch water, turn the valve on slowly to see if you are getting water. If there is no water then you have a problem within the valve. If you have water then the problem is further up the line towards the faucet.

      The next I would take would be to remove the cartridge from the faucet, and again turn on the water and see if water sprays out from where the cartridge was mounted on the faucet. I would recommend placing a rag over the hole to control the spraying of the water. If water doesn’t come out then the blockage would be between the valve and the cartridge. If it does then examine the cartridge for debris, and the waterway to the diverter valve for the side spray if equipped.

      Basically follow the path of the water and see where the flow has stopped.

      Hope this helps,

  5. Jerry says:

    How do you get the bonnet off of a Kohler K-R10430? Tried turning and prying. Look at parts diagram. Does it just set on hub? Cannot see any threads or notches in parts breakdown.

    • Redwood says:

      Hi Jerry,
      The bonnet should unscrew, if the cartridge has been leaking keeping bonnet wet you may have to soak it in vinegar to break the mineral deposits down. Grease the threads when reassembling so it comes apart easier next time.

  6. Sal says:

    I have a 2-handle bathroom faucet handle that broke off from the middle of the base where the handle pivots for on/off. The screw is still in the base. Not sure how to proceed. Will I need new handles or how will I re-screw the handle back?

    • Redwood says:

      Hi Sal,
      There are a few different ways the Kohler Forte Lav Faucets attach depending on the model of the faucet I’ve included a few here in a picture. You’ll be better off finding the specific diagram of the parts either in your original installation guide or on the Kohler website. The handles are normally retained by the crew and part you see remaining down inside the faucet body and the screw has either come loose or, a part has broken. You’ll need to shut off the water to the faucet and most likely unscrew the uppermost remaining part on the faucet body to gain access to the screw and retainer part. Sorry to be so general but without a specific model it has too many variables. In some cases if the part you are trying to unscrew has been wet you may need to soak it in vinegar to remove a mineral buildup to get it to unscrew, they are never easy. The picture below shows a couple of the common handle configurations on the Kohler Forte 2 Handle Lav Faucets.
      Hope this helps,

      Kohler 2 Handle Lav Faucet Handle Breaking

  7. George Chabalewski says:

    I have a K-10433 spray head that has been leaking from the handle at its joint with the hose. When I unscrew the spray head, I can see that the part that remains on the hose has a round white plastic looking washer that I think is designed to stop any leaks. It appears to have a section missing from the washer, however. I don’t know what is causing the leak whether it is a bad seal in the screw-on portion of the hose, or if it is that washer. Is there a way to take that end attachment off the hose? Can you replace that part or must you replace the entire hose and spray head unit? Thanks.

    • Redwood says:

      Hi George,
      Most likely the washer is bad, it should not be missing a chunk. The picture below shows the Kohler part numbers for that area of your faucet. The parts may be obtained from Kohler under your warranty by calling 1-800-4KOHLER. If the hose is bad the part number for the hose is K-114379.

      Kohler K-10433 Spray Head Parts

      I do not recommend using non-oem or, universal parts in this application.

      Hope this helps,

  8. salman says:

    I have my Kohler bathroom faucet installed(lever single handle & hole), problem is that when I turn on the water with both hot and cold knobs open from the back end, the lever of the faucet doesn’t turn off water at any position possible. It does stop the water when a single knob (hot or cold) is opened from the back end.

  9. Denis Scarpinato says:

    Diverter valve does not change flow of water from the horizontal out flow to the vertical cleansing spray .
    How do I repair or remove valve?

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