How do I remove broken cast iron closet flange from PVC pipe

**Morbius** · 08-31-2010, 08:31 AM

I just removed my toilet from 2nd floor bathroom due to leak and found a broken closet flange. Never having installed one and since I don't want to go hammering blindly and bugger something up, can anyone tell me how they are installed and what is the best way to replace it.

**jadnashua** · 08-31-2010, 11:32 AM

You sure it is cast iron? The only cast iron flanges for PVC pipe use either a clamp or a compression fitting to hold them to the pipe. Depending on the brand, you might just twist it out, or you may have to back off on some screws to loosen the clamp (often this clamp is internal). Now, if it is plain painted steel ring on a solvent welded toilet flange, they do make repair rings. You cut or pry the old one off, and the new replacement is hinged and fits into the groove, then you screw it to the floor, which holds it in place. A picture would help.

**shacko** · 08-31-2010, 02:43 PM

jadnashua: >>>The only cast iron flanges for PVC pipe use either a clamp or a compression fitting to hold them to the pipe.<<<

This is just information, in the old days many flanges were packed and poured to pvc.

**jadnashua** · 08-31-2010, 05:47 PM

How did you keep the lead from melting the pvc? If it is actually leaded to the pipe, you could probably whack it with a hammer and break the cast iron. Or, drill out some of the lead, then pry that out, and wiggle the thing off.

hj · 09-01-2010, 06:24 AM

quote; This is just information, in the old days many flanges were packed and poured to pvc.

1. There are no "old days" for PVC drainage.
2. I have NEVER seen it done, and if it had been, the flange would pull off the pipe fairly easily, unless the process of pouring HOT lead and HAMMERING the lead down to calk it, deformed the PVC and created a "belly/groove" to keep the joint in place.

**shacko** · 09-01-2010, 03:13 PM

Originally Posted by hj

quote; This is just information, in the old days many flanges were packed and poured to pvc.

1. There are no "old days" for PVC drainage.
2. I have NEVER seen it done, and if it had been, the flange would pull off the pipe fairly easily, unless the process of pouring HOT lead and HAMMERING the lead down to calk it, deformed the PVC and created a "belly/groove" to keep the joint in place.

I'm talking about the early 60's, that's the "old days" isn't it? Back then you couldn't use gaskets on the inside plumbing which keep being the rule even after they approved PVC+ABS.

In the early days of plastic you were only allowed to use it for the stack vent going thru the roof, another lead joint. Floor sinks were also packed and poured. Floor sinks and flanges were poured the same way, the lead no hotter then it had to be to pour, you then waited until it cooled off before you caulked it.

You didn't miss the stainless tube they use in lieu of copper DWV, did you?

PS: They still make PVC soil pipe adaptors that are pack and pour

**shacko** · 09-01-2010, 03:19 PM

Originally Posted by jadnashua

How did you keep the lead from melting the pvc? If it is actually leaded to the pipe, you could probably whack it with a hammer and break the cast iron. Or, drill out some of the lead, then pry that out, and wiggle the thing off.

If you hit it with a hammer the PVC would probably crack, drilling it out is the common way to do it.