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How to Fix a Running Toilet

Learn how to fix a running toilet in this Howcast plumbing repair video with expert Tim Flynn.


"I'm Tim Flynn and I'm the owner of Winters Plumbing and Heating in Cambridge, Massachusetts. Winters Company offers plumbing, heating, cooling. If you need service today; we're the business to call. My website is I'll be talking to you today about plumbing.

How do you know if you have a leak in your toilet? There's a couple of ways you can figure that out. Number one, you might need some food coloring or a dye tablet, which I'm about to show you. It's really difficult to see a leak on white shiner, especially with water, so if you wanted to see this bowl with a little bit of water in it. A running toilet can literally cost you hundreds and hundreds of dollars, if left unattended. If you hear a toilet filling in the middle of the night, that's not a good thing.

So what I'm going to show you right now is a little dye tablet that we put in the back of your toilet tanks. I'll take the dye tablet, I open it up, put the contents of the packet inside the water basin here, and then I let it sit and wait for about 5 or 10 minutes, so if blue shows up inside the bowl, we have a leak so let's take a peek. It's blue. So we have a leak.

Alright, so we have a leak in the toilet from the tank to the bowl, and usually the situation is a flapper. So, the first thing you want to do is take that flapper that you have in your toilet with you. There are a bunch of them to get, because if you didn't take the one with you it's going to be very difficult for you to match up to what you really have. And the toilet that we're working on? This is a genuine part for that manufacturer, you can see it has that yellow float on it. This float actually helps keep this flapper up while the water's passing underneath it and it lets it fall back down as well.

This is our replacement part for our flapper that's leaking inside this bowl, inside this tank. So what I'm gonna do is, take out the old part and basically how it comes out is, you'll see that it snaps in on the other side. So you have to use some firm pressure to pull up, but you don't want to use too much, it is plastic so you want to be careful that you don't snap it, twist it, you want to be able to lift it straight up.

We're going to disconnect the chain, and you see this chain is quite long, and you don't want to have as much chain. Once you make the adjustment, you want to either clip off or break these links. We have our new piece ready to go in, and it goes in the same way that it came out, and you want to be able to reach in and you're going to want to snap these back down by going straight over the top, and you should hear a click--there's one! And then you're looking to hear it click again--there's two! You want to make sure that our chain has enough links, but not too much, and this is kind of a trial and error thing, so you want to put that one there... let me give it a little test to see how it works. Then we're going to fill the tank back up. Okay, I'm happy with the way it works. Okay, so you just fixed the flapper in your toilet."

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