I've got a 10 year old Gerber toilet. Toilet Model # 21-552. Tank Model # 28-559, 10" rough in, 1.6gpf. It takes Flapper part # G0099647. I verified these numbers with Gerber customer care and a couple online parts places. Approx. 5 years ago I replaced the flappers on all three toilets in my house as they were starting to leak. I ordered the flapper part # listed above and the new ones I received worked great and stopped the leak. Recently I had to do this again as 2 of the 3 toilets in my house started leaking, where they would run to fill a slow leak in the tank. So I ordered 2 new flappers, same part number and put them on. They won't seal. The new ones leak worse then the old ones. Could my flush valve or fill valve be wore out and need replacing??? In other words it isn't the flapper but the flush valve? Thanks for your help.
Help with Gerber toilet flapper or flush valve leak
- Thread starter seedman76
- Start date
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jeffmattero76
Well-Known Member
You may want to rub a scrungie sponge around the top of the flush valve, where the flapper seals. There may be some sediment buildup there.
Jeff Handy
Pro Handyman, NOT A Pro Plumber
Jeff is right, clean off the seat of the flush valve, minerals or slime can build up on the edges and ruin the seal.
If you are not sure if the fill valves are possibly part of the problem, flush the toilet, let it fill up all the way, then turn off the water supply to the toilet.
If the water level drops, the flush valve or flapper needs work.
If the water level holds, then the fill valve was the problem, it was still slightly trickling when it should have shut off.
So replace that.
If you are not sure if the fill valves are possibly part of the problem, flush the toilet, let it fill up all the way, then turn off the water supply to the toilet.
If the water level drops, the flush valve or flapper needs work.
If the water level holds, then the fill valve was the problem, it was still slightly trickling when it should have shut off.
So replace that.
Guys, thank you for your replies. Good info. I used a scrub brush to clean the seat of the flush valve per your suggestion. Afterwards I ran my finger around the seat and it feels smooth. I then tried both my old flapper and new flapper (both same part #) and both continued to leak. I can hear the water trickling out. The new flapper leaks worse then the old one. I’m assuming it’s my flush valve and the seat has gone bad. I ordered a new one today and will try it once it comes. Hopefully replacing it is easy. I haven’t looked into that yet. Thanks again.
Jeff Handy
Pro Handyman, NOT A Pro Plumber
Are you sure that is your tank model number?
Maybe you meant 28-595, or 28-590?
Anyway, a lot of them take the same flapper.
It could well be that the flush valve or its gasket is leaking, as you suspect.
You could change the whole flush valve, or just the gasket.
But you can get the whole flush valve that comes with a new flapper, very cheap.
This place has good prices.
https://www.plumbingsupply.com/gerbertoiletparts-viper.html
But before I would go taking off the whole tank to change the flush valve, I would go to a big box store or hardware store, and buy two or three “universal” 2 inch flush valve flappers from Korky and other vendors, for 1.6 gpf toilets, and see if they work.
Like this, for example.
https://www.amazon.com/Korky-100BP-Performance-Toilets-Long-Install-Made/dp/B00E5ICW0E
Make sure the spacing on the “ears” of the universal flappers you are buying is the same as your old flapper.
And the arms are the same length, to the center line of the flapper seal.
Bring an old flapper with you to the store.
Maybe you meant 28-595, or 28-590?
Anyway, a lot of them take the same flapper.
It could well be that the flush valve or its gasket is leaking, as you suspect.
You could change the whole flush valve, or just the gasket.
But you can get the whole flush valve that comes with a new flapper, very cheap.
This place has good prices.
https://www.plumbingsupply.com/gerbertoiletparts-viper.html
But before I would go taking off the whole tank to change the flush valve, I would go to a big box store or hardware store, and buy two or three “universal” 2 inch flush valve flappers from Korky and other vendors, for 1.6 gpf toilets, and see if they work.
Like this, for example.
https://www.amazon.com/Korky-100BP-Performance-Toilets-Long-Install-Made/dp/B00E5ICW0E
Make sure the spacing on the “ears” of the universal flappers you are buying is the same as your old flapper.
And the arms are the same length, to the center line of the flapper seal.
Bring an old flapper with you to the store.
Make sure the tube from the fill valve is not to far down in the overflow pipe. It will cause a siphon action.
I replaced my flush valve but now I’ve got a new problem. My left side (as I’m looking at the tank, one closest to fill valve) tank bolt/rubber gasket is leaking. The bolt has a rubber gasket inside the tank and nothing on the underside/outside...just a white plastic nut. I went to the hardware store and purchased a new rubber gasket but am having the same issues with it. I tried the new gasket a couple ways...tightening the nut down pretty tight and then tightening it just a little bit. Thinking maybe I was over tightening it. Nothing seems to help. It still leaks. I also tried both gaskets stacked on top of each other and it still leaked. Any other tricks or suggestions???
Jeff Handy
Pro Handyman, NOT A Pro Plumber
Try adding a thin layer of teflon pipe dope to all the surfaces making the seal that is leaking.
So about a quarter sized ring around the hole in the tank, a little more on both surfaces of the rubber washer, and a very thin coat under the head of the tank bolt.
Do this to all the tank bolts.
Also make sure the tank china is totally clean first, tanks get slimy and that can ruin the seal.
If this does not work, then try adding another rubber washer, then a stainless steel washer and then a stainless hex nut directly on the underside of the tank, on the other side of the hole that is leaking.
That way you can pre-assemble the tank bolts and rubber washers to the tank, and get a nice secure grip.
You can also add teflon pipe dope to the threads above and inside the new lower hex nut.
Also add some pipe dope to the face of the hex nut that contacts the stainless washer.
And a thin layer to the rubber washer surfaces, underside of tank hole, and new stainless washer surfaces.
This second washer and nut is not really meant to make a seal, it is there to support and stabilize the connection above it.
But it can also make a good enough seal to stop a slow leak sometimes.
So about a quarter sized ring around the hole in the tank, a little more on both surfaces of the rubber washer, and a very thin coat under the head of the tank bolt.
Do this to all the tank bolts.
Also make sure the tank china is totally clean first, tanks get slimy and that can ruin the seal.
If this does not work, then try adding another rubber washer, then a stainless steel washer and then a stainless hex nut directly on the underside of the tank, on the other side of the hole that is leaking.
That way you can pre-assemble the tank bolts and rubber washers to the tank, and get a nice secure grip.
You can also add teflon pipe dope to the threads above and inside the new lower hex nut.
Also add some pipe dope to the face of the hex nut that contacts the stainless washer.
And a thin layer to the rubber washer surfaces, underside of tank hole, and new stainless washer surfaces.
This second washer and nut is not really meant to make a seal, it is there to support and stabilize the connection above it.
But it can also make a good enough seal to stop a slow leak sometimes.
Jeff, great info. Thanks for your reply. I think I’ve got it solved. Turns out the leak was actually coming from the large black gasket that seals the tank to the bowl. My first time ever doing any of this and when I took the tank off that gasket stayed stuck to the bowl so I didn’t even realize what it was. When I put the tank back on I think that gasket was pinched or out of alignment. I didn’t realize all this until I did the second toilet. When I pulled that tank off the gasket came with it, stuck to the bottom of the flush valve. That made me go back to the first toilet looking for that gasket and discovering it was still stuck to the bowl. Once I pulled it off, realigned it and placed it on the flush valve, then tightened everything back up, all was good.
The new flush valves I ordered fixed the leaking flapper problem as well. Like you suggested the flapper wasn’t the issue and instead the flush valve was wore out where it seals at the flapper. Two new flush valves seems to have solved those leaks. Thanks again for your help.
The new flush valves I ordered fixed the leaking flapper problem as well. Like you suggested the flapper wasn’t the issue and instead the flush valve was wore out where it seals at the flapper. Two new flush valves seems to have solved those leaks. Thanks again for your help.
