I have a Kohler Santa Rosa toilet circa 2013. Water only fills the tank about 20% of the way - to the bottom of the center tube. I lifted up the center tube and noticed a red, possibly rubber, ring dangling off the bottom. I suppose this is the sealing between the tank and the bowl. Since there is no longer a tight seal, the water constantly leaks from tank to bowl.

tank sealing

I tried to remove the whole center tube to attempt to reattach the sealing, but I was prevented from completely removing the tube due to it being stopped by this disk thing. This "disk thing" is usually connected to the white tube, but I disconnected the tube during this repair. What are my options to repair the sealing if I can't get good vision of it and can not comfortably maneuver my hands around it?


  • New gaskets are available if you want to avoid having to take the tank off to replace the whole mechanism. So there must be a way to remove the cylinder to replace the gasket. Does the disk unscrew?
    – Alaska Man
    Nov 7, 2018 at 17:42
  • When I try to twist the disk, it doesn't feel like it can be removed. It torques slightly like a Twizzler candy, so if I twist even harder it might snap the plastic.
    – JoJo
    Nov 7, 2018 at 17:44

3 Answers 3


I found this video that appears to be for the same unit you have.

You should be able the twist the small disc 1/4 turn counter clockwise to free up the cylinder for removal.

The small disc is part of the whole unit so try grasping lower on the cylinder with one hand on the disc with the other. Yours may be stuck with grime, try gently working it.


I have done this. The cylinder thing is called the canister. The red seal should stay attached to the part below, that the canister rests on. Mine was squishy and I was able to temporarily reshape it until I got a replacement.

The entire tower part rotates about 1/4 turn counterclockwise, then lifts off easily. It seems fragile, as if it might break, but mine didn't. There are probably instructions on Kohler's website.

I know of no other option than to pay the overpriced $7 or so for an official replacement seal at HD or Lowes. The new ones are yellow and supposedly last longer.

Btw, if you ever replace the Fluidmaster fill valve that came with the Koehler, be careful that the new fill tube (white in the original) is not of a narrower OD, or else it will eventually come loose and spray sideways, which ends up on the floor somewhat. I fixed mine by wrapping with tape to make it have a greater diameter.

  • I replaced my faulty Fluidmaster 400A original fill valve with one from BrassCraft, which was better and also BrassCraft customer service help is far, far better -- in my experience with both.
    – Bob3411
    Nov 7, 2018 at 18:58
  • I just repaired mine after procrastinating 2 months. My red ring actually attached to the bottom of the canister, not the base. There's a groove that the ring fits into. I'm appalled by the quality of this ring. It's very loose fitting in the groove and it is bound to dislodge any time soon. Maybe I should have glued it in with Gorilla Glue. Oh well, maybe next time.
    – JoJo
    Dec 23, 2018 at 23:13

From your description, the red rubber peice fits on the bottom of the black shaft that slides up and down when you flush it. It's not the seal between the tank and toilet because that is out the outside between the tank and toilet. If it's too hard to put back on, or doesn't stay on, it might be easier just to buy a new flush valve assembly. This will require draining the tank and then removing it from the toilet to replace the flush valve which isn't hard to do.

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