Replace flush valve on old Kohler 3402PB?

Discussion in 'Toilet Forum discussions' started by markyyy, Mar 10, 2008.

  1. markyyy

    markyyy New Member

    Mar 10, 2008
    I've got an 18 year old Kohler 3402PB that will give us phantom flushes about every two hours. I did the food dye test in the bowl and noticed the bowl was turning color after 30 minutes or so, so it looked like a leak. I drained the water again, filled it slowly before it got to the level of the flapper and noticed that the dye was leaking, so I'm pretty sure the leak is coming from the flush valve seat. Does anyone have experience replacing one of the flush valves on an old Kohler?
    It looks like the previous owner bought some generic flush valve and just sealed it with caulk -I attached a pic
  2. markyyy

    markyyy New Member

    Mar 10, 2008
    Here's the picture

    Attached Files:

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    Attached Files:

  4. Redwood

    Redwood Master Plumber

    Dec 15, 2007
    Service Plumber
    Ah yes the old Kohler Rialto... Better you than me!
    Are you detectng my love of this toilet yet?
    Problem is Koher tried about 5 different proprietary flush vaves on this lemon and never did get one that worked all that well. As you can see the aftermarket replacements are probably worse and whoever bastardized that toilet picked the worst of the worst. You could go to this link and guess which one you need from Kohler it will arrive about 3 weeks after you place your order and it may work. Maybe... Buy Lotto tickets you have a better chance there.

    Or, what I would do is take off the seat, put it out on the deck, fill the bowl with dirt and use it as a planter. As for the hole in the bathroom floor I would cover that with a brand bew Toto toilet. They do not have the parts nightmare and they flush quite a bit better than what you had there before.
    Last edited by a moderator: Oct 12, 2015
  5. markyyy

    markyyy New Member

    Mar 10, 2008
    Much obliged for the link to Kohlers parts site. They have 5 different valves , some with what look like little flanges that you screw in and the others with a small nub on the flush valve assembly itself, with another washer that I'm guessing fits on the other side of the tank. Is it just a matter of twisting these valves into place, or is there some other funky way of getting the valve seated?
    OTOH, turning this into a planter looks more and more like a viable option...
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    You've hit upon on of the problems with Kohler stuff...they change designs on a whim, it seems, and their parts book looks more like a phone book. That is one reason why few stock parts...just too many to deal with.
  7. Master Plumber Mark

    Master Plumber Mark Master Plumber

    Feb 6, 2005
    Sensitivity be caring and loving to a
    indianapolis indiana - land of the free, home of
    if I were you

    I have gotten away with murder in the past
    like I see down in that toilet tank....

    I suggest you simply change out that fluid master flapper
    and leave that silicone job alone....

    it might actually be best to dry out the whole area and
    smear another 1/2 inch of silicone on top of what is already there....
    and just do the new fluid master seal...

    once you tear that off you are basically opening a can
    of worms.....
  8. grazzy

    grazzy New Member

    Nov 1, 2007
    ferguson's carries the kohler conversion flush valve kit for $37 bucks. it has three anchor bolts to anchor it into the triangle in the bottom of the tank. the flapper might still leak a little, and if it does get a plumbpak 23592 or one suggested by redwood in another thread. i'd clean all that silicone off with a razor blade and put some silicone under and over the seal before tightening the anchor bolts. be careful you don't overtighten and break the porcelain. also, you might want to immediately substitute a cheap plastic chain on the flapper, because the steel ones kink often.
  9. markyyy

    markyyy New Member

    Mar 10, 2008
    Thx a bunch everybody -- I'm going to order a replacement valve and give this a shot. I'll let you know later how it goes.
    I'll start looking at Toto's in the mean time just in case this doesn't work out..........
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