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.


  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

    • 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.

    • 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.

  2. 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.

    • 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,

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