Mansfield 160 Toilet Problem - Please Help!

I recently noticed my toilet running and decided to try to fix it. I first looked to see if any water was draining into the bowl and that was not the case so then I decided to search around the internet and found out I probably needed to replace the ballcock fill valve discs that are right inside the cap. So I bought a few from a local plumbing store and replaced them, however now the problem I have is different and this is happening on 2 of my Mansfield toilets.

This is what happens ..

I flush the toilet and the water begins to rise. It rises up just before the top of the flush valve and then when the ball gets high enough it forces fill valve to shut. Then within 5 or so seconds it releases and then you hear a water running noise for about a second. It gets quiet and then in another 5 seconds it releases. By this time the water is moving a little bit making the ball move up and down causing it to almost continuously release and refill. After about 10 times it finally stops doing it.

I have tried putting everything back together countless times. Tried adjusting the water valve so it doesn't fill up as fast too. I also tried turning over the fill valve seal in the ballcock.

please help... this is taking me forever

The flapper is leaking and as the level in the tank drops, the fill valve comes back on. Replace the flapper.

I checked that first ..

There is not a single drop of water getting through the flapper into the toilet bowl.

A little dye or, food coloring in the tank will tell you differently.

I suggest you replace the Mansfield fill valve with a Fluidmaster 400A. It will not have that problem.

Video of my toilet problem

I decided to take a quick video of what is going on with my toilets.

http://www.jobitat.com/toilet.html

I tried some dye and there doesn't appear to be any leaking at all from the flush valve in the center.

Any other ideas?

Is there water in the float ball? The extra weight may cause the arm to drop, letting in more water, until it reaches the final height. I got tired of dealing with all the problems with the ballcock and flush tower and ended up replacing all the tank guts in the 3 Mansfield toilets that the builder supplied in my house. I replaced with fluidmaster parts (available at HD), and the toilets worked much better.

http://www.fluidmaster.com/html/fill_products_400ak.html

Ok

Would I need to replace everything or just the fill valve?

While your in there replace everything and you won't have to touch it for a long time...include the supply line replacing with a braided stainless flex line...

Replacing just the fill valve would probably fix your problem - it's an easy change and you wouldn't have to pull the tank. But in my experience, the seal on the bottom of the flush tower will eventually cause problems as well. That's why I replaced everything.

valve

I would suspect you have a pressure reducing valve and it is defective. The ball closes the valve when the float can overcome the dynamic pressure but when the system pressure increases it overcomes the float and forces it open. That reduces the pressure so it can close again, but then the cycle repeats. Each repetition adds a little bit of water to the tank and eventually the water level reaches the point where the float is able to overcome the pressure and it stops permanently.

Question

Where would the pressure reducer valve be? I don't see anything that would resemble something like that. Should I get the "mansfield" discs or are the off brands just as good?

Oh also, how tight to do I put the ballcock cap on? Do i need to put anything on the threads so it seals completely?