Kohler toilets: Bad anchor bolt design for toilet seats -- with no solution

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Feb 24, 2021
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We purchased a Kohler Pursuade Curv toilet for our beach house in 2013. When the ‘Quiet Close’ lid recently failed I tried to remove the seat to install the new Quiet Close part.
To my surprise, the bolts were frozen in the anchor inserts. One anchor finally stripped and cracked into two pieces, as shown below. Fortunately, the toilet itself was not cracked in the process.

The cause of this problem was immediately apparent: the anchor was made of aluminum and the bolt is stainless steel. These two metals can never be used together in fasteners (and many other applications) due to galvanic corrosion. See:
https://en.wikipedia.org/wiki/Galvanic_corrosion. This is particularly true with a toilet seat, where the fasteners will be exposed to water, acidic / alkaline solutions and cleaning products, which boost galvanic corrosion.

This problem affects many Kohler toilet models, produced over two decades.

Kohler #84999 replacement anchor / bolt kits have the same problem. I ordered a Kohler 84999 kit; unfortunately, nothing has changed. The anchors are still aluminum, with stainless steel bolts, as shown below.

I sent letters to Kohler senior management – and quickly received a follow-up call. The Kohler representative explained that this problem was due to a supplier who changed the insert from brass to aluminum. A new anchor had been designed that was 100% stainless steel, and Kohler would ship two kits to me ASAP plus refund the cost of the first replacement kit I had ordered.

This was exactly the high quality customer support I expected from Kohler. The new anchors arrived - #1461673.

Unfortunately, another engineering design error! The new #1461673 anchor bolts will only fit Kohler toilets with 1/2" holes. Our Persude Curv and many others have 3/8" holes. The Kohler engineering / design team apparently forgot to check the dimensions on all of their recent models! Two major and basic design errors in a row -- incredible! It would have been easy to design a new anchor bolt that would fit both. Note: Kohler's customer service has been excellent. The problem is in Kohler's engineering / design team.

Here are the models that the #1461673 anchor bolts will not fit, produced from 1990 to 2015:

  • K-4441 Persuade
  • K-3386 Rialto
  • K-3384 San Raphael
  • K-3434 Rosario
  • K-3435 San Martine
  • K-3398 & K-3399 San Raphael Pump Flush Toilets
The Kohler support rep said they are working on a third design that should fit all models -- which may be available in "6 weeks to 6 months". I wrote to Kohler senior management again and recommended that they simply buy a stainless steel toggle bolt from Toggler that will fit 3/8" holes. Don't waste more time and money on Kohler's hapless engineering / design team and "version #3". Thousands of Kohler customers have this problem, and the solution is quick and cheap. Buy it, don't build it.

If your Kohler toilet has this problem, there are two potential solutions: First, carefully remove the frozen bolt and anchor. You may have to drill out the aluminum anchor. (1) Replace it with a standard #84999 kit -- but apply a generous layer of thread lubricant to the bolt before you insert it. Then contact Kohler and wait for their 'Version #3' design and replace the #84999 bolts when the new kit arrives. (2) Order a set of Toggler stainless steel, 3/16" toggle bolts, which are available on Amazon for $8. The 'wing' is 7/16" wide, just slightly too big for 3/8" holes. With the bolt in the wing, carefully compress the wing a bit with a vice or pair of channel lock pliers. You only need to reduce the width by 1/16". Go slowly and make sure the bolt doesn't bind in the threaded hole. After you've reduced the width of the wing to 3/8", you will find that Togglers are easy to install.

Here are the photos:

Original Kohler anchor - 'frozen' due to galvanic corrosion:


Kohler #84999 replacement kit -- has the same problem:


New Kohler #1461673 anchor bolts -- will not fit in many Kohler models. Stainless steel bolt and 'wing' with silicone sleeve:




Toggler 3/16" stainless steel solution:



Well-Known Member
Feb 16, 2015
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I noted another design problem with respect to my Rochelle toilets. Kohler doesn't make toilet seats and the seat manufacturer failed to note that the Rochell bowl rim (that the seat rests on) slants inwardly. The somewhat hard plastic bumpers were installed radially so they contacted the rim only at a small area They would shatter the first time the seat slammed down. Later versions (much later) had bumpers that were installed tangentially to the rim rather than radially. So with two Rochelles one of mine has tangential bumpers the other has broken radial bumpers. I haven't checked lately but haven't been able to find appropriate aftermarket bumpers. They would need to be clear silicone to work with colored seats.


Well-Known Member
Jan 3, 2017
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It is in the plumbing code that all hardware shall be brass ,plastic, or corrosive resistant in a toilet .

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