Cast Iron Prep For Oatey Replacement Flange

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Jeff Handy

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A friend is probably going to ask me to help him with a rotted out cast iron toilet flange.
The slots are rusted and too wide.
Maybe he can add stainless or galv washers to grab the slots, or a flange repair kit, etc.
I am not on site and don’t have pictures yet.

But it seems we will be using the Oatey replacement flange that will sit over the old flange, and slip down inside the cast iron pipe and seal against the sides with rubber, tightened up by the three cams.

I have not used this type for a long time.
Last time, the pipe was really clean and sound, just a quick wire brushing and it was good to go.

This one sounds like it is rough and pitted.

I was thinking of heavy wire brushing, then cleaning with alcohol, then giving the sides a primer coat of toilet wax rubbed on it, to create a better surface for the rubber to seal against.

Any thoughts, or better ideas?
 

Jeff Handy

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I never have.
I would have to drill out the old joint, or somehow get the old flange off.
Melting lead sounds scary, but I have heard it works well, once you get the hang of making that joint.
Then just tap it down with something blunt, to pack the joint, if you don’t have the irons.
 

Jeff Handy

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Another thing is, in old houses like this, sometimes the old flange is doing a lot to support the cast iron pipe.
Because people have done drain or stack repairs over the years and added rubber couplings that can sag, once the flange stops holding everything up.
 

Twowaxhack

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I usually break the flanged part off with a hammer snd the try to crack the rest of the flange body vertically. Once the flange is removed I chisel through the lead and try to pry it out with a claw hammer.

No drilling and I’ve never had a stack drop or anything move while replacing a flange.
 

Jeff Handy

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My buddy was able to salvage the old cast iron flange, as is, the slots were only sloppy near the outside edge.
By using extra nuts and washers, as I advised, he was able to anchor the flange bolts nice and tight to the flange. so they would not wander into the sloppy area while being tightened.
However, when he was done, he wondered why there was a five inch gap behind the tank.
The client had given him a ten inch rough in toilet, to set onto a fourteen inch rough in flange, and he only noticed when he assembled the tank onto the already mounted bowl.
 

Jeff Handy

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As far as the pipe sagging etc, I tend to look ahead to doom and gloom worst case and plan for that.
So when things go better I am happy, but am usually prepared for things most folks would say don’t worry about, till suddenly you are left with a crap pile and worst case came calling with a big evil grin.
 
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