Kohler GP83996 4.06-Inch by 2.56-Inch ID Flush Valve Gasket

Simple replacement for a gasket which was dissolving. Easy fix. Worked great and no leaks

I bought multiple third-party gasket and couldn't get them installed. What I found with off-brand gaskets is that the rubber material is quite different from that used by Kohler. It was so difficult to compress that I couldn't install the flush valve assembly. The hack to getting even the Kohler gasket installed is to compress-and-freeze the gasket, place it on the valve assembly, and, before it can thaw and expand, insert the gasket and rotate the assembly into place. That trick doesn't work with third party gaskets I tried. It worked perfectly with the official Kohler gasket.

It feels like the most midlife thing to do: a review for a toilet tank gasket! Anyway, I have a Santa Rosa one-piece toilet and the gasket was disintegrating from using cleaners in the tank itself (bad idea). This gasket fits if you put it in hot water for 5 minutes before installing it. Needs a good bit of strength for the flange to clip back onto the bottom of the tank but it works. Sure beats calling a plumber for $150!

It has to be compressed and twisted. I oiled it and compressed plastic piece with a softball. Thanks youtube.

Recently I replaced the flapper and this seal in our Kohler toilet that I installed fifteen years ago. With service like that, why would I not replace them with the same original factory parts? I seemed like a no brainer. Very simple to remove the old one and install, as a crippled old man (like me) can do it. It is very well made.

Well, I needed to let some time pass before writing my review on this product. The reason for this is not due to the gasket itself, but to how difficult it was to install it and how frustrated it left me. The gasket is pretty thick in order to create a tight seal. The existing gasket on my toilet needed replacing, so I thought this would be simple. Unfortunately, my tank is very narrow and I could not get any leverage to push the Flush Valve back onto it and get the teeth of the valve to hook under the tank. I tried for a few days, coming back after frustration levels died down, only to fail again and again. I then resorted to calling a plumber thinking for sure that he could get this in with some wisdom gained from years of experience. Alas, I left him alone in the bathroom for 30 minutes while he tried and tried to get this in there to no avail. Being a plumber who is also a problem solver, he went out to his van, took some PVC pipe, a Dremel device, a drill and four screws and created a device whose sole purpose will be to replace these gaskets. See picture for the device he made. This device allows you to easily push down on the flush valve and gasket, then turn it while keeping sufficient pressure. The plumber was worth every dollar to finally get our toilet working in our master bathroom again. In summary, the gasket works just great, but the installation is beyond difficult.

My Kohler, Santa Rosa, one piece after more than 12 years needed a complete overhaul including the tank gasket. I read and tried a couple ideas on how to get this done but ended up with my own solution. Easy peezy once I figured it out. Prepare the gasket as shown in the pic. Compress evenly to at least half its depth with wood blocks and "C" clamps. Then into the freezer for about 3 hours. Have all components of tank ready for install then remove gasket from the assembly. Olive oil on both upper and lower surfaces will give you extra time for finite adjustments. You'll have about 3 or 4 minutes before the seal expands enough to make basic install more of a challenge. Install flat side down. Slips right into the tank with no effort. Align as necessary to be square with rear of tank then install all other tank components. By this time the gasket will have tightened substantially but with effort a little adjustment can be made if required. For me, in another 30 minutes or so the gasket swelled to a tight seal with no leaks. Some warm water into the tank could speed the process. Good luck!! It really was very easy with this procedure.

Over the years these gaskets deteriorate while sitting In toilet tank water Therefore, I always keep a few on hand for quick replacement.