Help! Stripped Cast Iron Thread on Shower Drain

[MikeGA]

I'm removed the concrete shower pan from a 1960 shower. As I was removing the drain, it's just kept turning and not coming off. Any ideas on how to remove the drain so that I can also preserve it? I want to install a new type of shower pan.

 

[Jadnashua]

It appears that the riser is leaded into the hub of some cast iron. I think I'd try to remove that whole thing, riser plus drain from the hub. To build it back up again, you'd need to find the proper sized donut, then that should let you use a PVC riser and then any drain you want. There appears to be enough room to make that work, but you'd have to measure carefully the depth of the drain and how deep the pan is relative to the hub below.

To remove the riser from the hub, generally, it works best to drill a bunch of holes in the lead, then you can pry out the lead and then clean up the interior of the hub so a donut will seal well. https://www.fernco.com/plumbing/donuts-o-rings/donuts

It's important to get the right size - while the PVC is standard, the actual dimensions of CI hubs is not. Just like Goldilocks and the porridge...you want it just right to work!

 

[Sponsor]

 

[MikeGA]

It appears that the riser is leaded into the hub of some cast iron. I think I'd try to remove that whole thing, riser plus drain from the hub. To build it back up again, you'd need to find the proper sized donut, then that should let you use a PVC riser and then any drain you want. There appears to be enough room to make that work, but you'd have to measure carefully the depth of the drain and how deep the pan is relative to the hub below.

To remove the riser from the hub, generally, it works best to drill a bunch of holes in the lead, then you can pry out the lead and then clean up the interior of the hub so a donut will seal well. https://www.fernco.com/plumbing/donuts-o-rings/donuts

It's important to get the right size - while the PVC is standard, the actual dimensions of CI hubs is not. Just like Goldilocks and the porridge...you want it just right to work!

Are you recommending that I remove the entire cast iron riser all the way down to the weld? That would be very difficult given the space. I think the best I could possibly achieve would be to sawzall flush to the floor the cast iron riser and the insert a no hub? Thoughts on that?

 

[MikeGA]

It appears that the riser is leaded into the hub of some cast iron. I think I'd try to remove that whole thing, riser plus drain from the hub. To build it back up again, you'd need to find the proper sized donut, then that should let you use a PVC riser and then any drain you want. There appears to be enough room to make that work, but you'd have to measure carefully the depth of the drain and how deep the pan is relative to the hub below.

To remove the riser from the hub, generally, it works best to drill a bunch of holes in the lead, then you can pry out the lead and then clean up the interior of the hub so a donut will seal well. https://www.fernco.com/plumbing/donuts-o-rings/donuts

It's important to get the right size - while the PVC is standard, the actual dimensions of CI hubs is not. Just like Goldilocks and the porridge...you want it just right to work!

My other question is the link you sent me. I never used this type of a donut before...are you saying this donut fits inside the cast iron riser?

 

[Helper Dave]

jadnashua's idea is right on. If you look at the hub--the big thick pipe the riser sits inside--, you can see the layer of lead between it, and the riser pipe. To drill it, either go at an angle (you're not worried about ruining that inner pipe, since you're just getting rid of it), it, or sawzall the drain off so you can drill straight down.

It's not a thick layer of lead. It's more time consuming a job than it is difficult. A hammer and flathead clear it out of the hub after you've made it swiss cheese.

The donut he linked replaces that lead and horsehair layer (rope) in the hub.

 

[MikeGA]

jadnashua's idea is right on. If you look at the hub--the big thick pipe the riser sits inside--, you can see the layer of lead between it, and the riser pipe. To drill it, either go at an angle (you're not worried about ruining that inner pipe, since you're just getting rid of it), it, or sawzall the drain off so you can drill straight down.

It's not a thick layer of lead. It's more time consuming a job than it is difficult. A hammer and flathead clear it out of the hub after you've made it swiss cheese.

The donut he linked replaces that lead and horsehair layer (rope) in the hub.

I get it now. I never even knew this could be done. I did additional research and read that heating it up would help. Do you think this would make it more difficult since the heat will heat up the lead and possibly melt it?

 

[Helper Dave]

I would avoid the potential for toxic fumes, and not bother with heat. Lol

It's soft enough as it is, imo

 

[WorthFlorida]

The lead is not that thick, maybe no more than 1/2" to 3/4" Under it is oakum that holds back the lead from going down the drain. With a long drill bit you can eat away the lead and/or with a long screw drive you can chip it way until you get to the oakum. Then lightly tap the pipe side ways to loosen it and wiggle it out.