View Full Version : Cast Iron Toilet Flange

09-24-2012, 08:24 AM
Hello all

I have a house built in 1947, and the sanitary lines are all cast iron. In one bathroom, the flange has a broken bolt for the toilet connection. The bolts appear to have been leaded in with the flange. In other words, there is no slot to insert new bolts like I see in most new flanges. Was this a normal practice? If so, where would I get a new bolt to lead in? How was it typically done?

The flange is in good shape other than the one broken bolt however it is about 3/8" below the current floor due to an remodel. It seems too bad to replace it just because of the bolt, but I could do that. If I did, I see two types of replacement flanges. One seals on the inside of the pipe, and one on the outside. It seems like the type that seal on the outside would be better in this case because the inside of the pipe is pretty rough. I could lead in a new flange as well if I could find one, but it seems like replacing the bolt is the best bet if I can figure out how it is done.



Tucson, Az

09-24-2012, 10:05 AM
Might be an exception, but all of the flanges I've seen have either a single slot where you slide the bolt in from the side, or a T-slot, where you have more flexibility on where to mount it. But, with the flange below the finished floor, you may not be able to slide it out, even if it did exist. A good wire brushing may reveal it. Do not use steel bolts again! Use brass or SS, not brass plated steel or plain steel. They make flange extension rings and flange repair rings. One or the other or a combination of both would get you a way to anchor new bolts to the existing flange. Using an internal flange is not the best choice, especially on an older pipe with corrosion, especially if it is a 3" pipe (4" does work, though).

09-24-2012, 10:17 PM
Thanks Jim.

I am guessing that this one has the single slots on the side, and they are full of lead. The bolt that broke was definitely not a closet bolt that slips into a slot. Maybe I can remove the lead and use a closet bolt but the slots look a little wide. I could use a washer I guess. I attached a photo of the flange, the point where the broken bolt was, and a picture of what I think the broken bolt may have been. It looked like it was leaded in at some point. Also, the repair rings I have seen don't seem like they would attach well to a flange with just the two closet bolts. There are no other holes or slots in the flange.

Thanks again for your help.


Gary Swart
09-24-2012, 11:18 PM
I realize you want to avoid hiring a plumber, but that is worth considering. The flange is not properly set in the first place. It should be on top of the finished floor. Now, you can get by with a recessed flange using repair rings or extra wax rings, but the flange looks to me to be in questionable condition. If the flange does not hold the toilet from rocking, the seal will be broken and you will have a leak. I'd fix it right now and be assured it will last for many years. The potential damage from a leaking toilet would make the plumbers charge look pretty reasonable. Not many non plumbers can work with lead. It's up to you, but I'd sure give a plumber serious consideration.

09-25-2012, 07:09 AM
Thanks Gary

You make a good point. I am guessing that lead connections and joints are not commonly installed anymore even on repairs by plumbers. That's why my original post alluded to repair flanges that seal on the outside like this one from Oatley


It may not be clear in the picture, but the original flange is in good shape although it is below the finished floor. If I can get the replacement toilet bolt installed properly I can probably save it.