Kohler 1-pc Rialto flapper leaks

**Muggins** · 10-20-2006, 11:06 AM

My Kohler one piece toilet has been working fine for
about 3 years, now, but recently, the simple rubber
flapper has been leaking at various rates after I flush.
Sometimes, it makes a good seal, but usually it slowly leaks.

So, I replaced the flapper but it still leaks sometimes,
not always. I've fiddled with the adjustment. I'm a
plumber (construction plumber, not a repair plumber)
and I'm supposed to know how to fix this thing, and it's
kinda embarrassing. Is there anybody ever had a similar
problem?

The drain hole to the bowl that the flapper seats on is
2 9/16" in diameter. The flapper measures 2 3/4" in diameter.
Not much overlap is there? Maybe an after market flapper
might work better, or what?

**Verdeboy** · 10-20-2006, 11:19 AM

I researched this a bit, and apparently there is some sort of design flaw here. People have had to try different brands of flappers before they found one that works. Kohler has even agreed to ship entire new flush valve assembly to some.

**Muggins** · 10-20-2006, 12:29 PM

Thanks for that quick response, Verdeboy.

A rubber flap seems to be such an uncomplicated and
simple valve design, it's a wonder that Kohler could design
something that didn't function very well, but they managed
to do so. The problem is so simple. The diameter of the
rubber flapper is an 1/4th of an inch too small.

I tried calling Kohler, but they couldn't help me because I
didn't have the serial number of the toilet. I got the impression
they didn't want to bother with it. "Can't help ya." was the
last thing I heard from them.

I'd be interested to find out what flappers work better than the
Kohler replacement flapper.

**Muggins** · 10-20-2006, 12:49 PM

At this site, they talk about the Kohler flapper
problem.

The recommendation is to use Korky flappers,
maybe a #58.

dx · 01-20-2007, 11:54 AM

Reviving this old thread because I have a client with same problem. Flapper leaks, new flapper leaks just the same.

This is the system with the rectangular standpipe. The flapper has a rectangular rubber "ring" that fits around the standpipe.

The problem is the chain pulls on the flapper sideways and the flapper comes back down not so straight. Works about 80% of the time, the other times you have to jiggle the lever.

I talked to Kohler tech and they appear to be aware of a design issue. They offered to send me a free "longer" actuating lever. Just got it in the mail. It's no different than the one already in the toilet.

Has anyone found a fix for this? Does anyone make a kit for replacing the entire guts of the toilet with something that works?

Thanks

**Verdeboy** · 01-20-2007, 07:17 PM

Most times, you have to cut off that rectangular ring with a scissors to get it to seat properly. Just hook the two remaining holes on the sides of the flapper over the hooks of the flush valve.

dx · 01-21-2007, 10:14 AM

Eric,

You are talking about a different system. The one I am talking about has no hooks, holes or any other mounting provisions.

See picture. The back part of the rectangle (thinner) snaps into a groove on the back of the rectangular tube.

**Verdeboy** · 01-21-2007, 03:01 PM

My mistake. Maybe you can replace the flush valve with a more universal one (that has the little hooks) and get a standard Korky flapper.

But before I tried that, I'd try adjusting the chain on the flapper you already have. You might need to leave a little more slack. Also, If the lever has a metal rod that is attached to the flapper, maybe you can bend it a bit to lift up the flapper straighter, or you can replace that lever with one that you can bend in such a way.

dx · 01-21-2007, 07:59 PM

Thanks Eric!

I already fiddled with the chain and all that. There is no room in the tank to even make a custom lever that could pull straight up on the flapper.

Took your suggestion and looked closely at the Kohler site. Lo and behold, their current parts diagram for the Rialto K3386 shows a standard flapper style with eyes and corresponding hooks on the rectangular tube.

Somewhere along the line they must have changed it when they realized the old style isn't working! All I have to do is update to the current Rialto flush valve.

Thanks again
DX

**gjhaag** · 01-10-2008, 03:21 AM

Guys I have the same frustrating problem witht the Kohler hinge flap. Whenever you flushed the flapper pulled to the left and wasn't completed seated. I bought a couple of different flappers (thinking there was a defect) and then started to research the problem a bit. However I figured out that I didn't have the flapper snapped into the ridged place holders in the back. You have to pull forward very hard and make sure that the rubber hinge is seated in the ridge. Once I did that, the flapper no longer pulled to the left when flushed. There are different heights of ridges. I snapped mine at the third ridge from the bottom. Hope this helps.

**grazzy** · 01-10-2008, 10:48 PM

i just fixed a stubborn rialto with the rectangular valve by taking a couple of rubber faucet washers and placing them on the hooks between the eyes on either side of the flapper and the flush valve tube. this keeps the flapper from having so much play when it comes back down. the best flapper is one i got at lowe's with the styrofoam on the under side. also had much better success after switching to a plastic chain. the metal one was always kinking.

hj · 01-11-2008, 05:16 AM

You are also referring to a different Rialto flapper. Kohler has a tendency to make revisions, creating many different parts for the same model fixture.

**Redwood** · 01-11-2008, 05:33 AM

Ripping that sucker out and putting in a Toto Drake would be a great fix!

It would give them a better flushing toilet too!

**grazzy** · 01-11-2008, 09:40 PM

Originally Posted by hj

You are also referring to a different Rialto flapper. Kohler has a tendency to make revisions, creating many different parts for the same model fixture.

you are correct, but i believe the one they are now selling is the rectangular valve with the hooks, and it has a problem similar to the one described in this thread with the flapper not seating correctly all the time. the fix for it was pretty simple. dx said he's about to try that valve and it may not completely resolve his issue without the modification i described.

**polishsausag** · 04-24-2010, 09:29 AM

Thank you for the great info in this forum. I figured it was a design issue with the hinged flapper and spent the earlier part of today looking for an appropriate replacement with some re-enforcement on the sides to prevent it from traveling. I was just about to send Kohler threats for new guts when I discovered (upon finding my model number, mine is K-3384-2 which is located imprinted in the back of the tank) that they have phased out the korky style cheap rubber flapper with a better one. 84995
Replaced by GP84995 http://www.kohlerserviceparts.kohler...f3b23a91dc463a

This new one seems to have a solid plastic stick that snaps into the Hinge slot, and sides with more rubber and grooves to keep the flapper in place. I am going to order one and see if it resolves the problem. Will try to post again if successful.