11:43AM | 02/17/03
Member Since: 11/26/02
33 lifetime posts
I am trying to remove an old plug (seems to be 3.25", not 3" or 4" like the standard ones) on a cast iron drain system. What are the tricks for getting these loose? Here is what I've tried:

-- Tapping around the plug with a nail set
-- Heating with propane torch and twisting
-- Applying WD-40 to threads

I can get a pipe wrench around the plug(outer threads are protruding enough to get a good grip), but it won't move. I don't want to start whacking on the pipe wrench because I don't want to disturb the old pipes.

What else can I try? I need to get this plug off so that I can clean the pipes under a tub.


04:04AM | 02/18/03
Member Since: 09/17/02
524 lifetime posts
If you can find a replacement plug just smash it out with a hammer. They usually breake easily. Find the replacement first.


08:25AM | 03/01/03
Member Since: 02/28/03
3 lifetime posts
I am having the exact same problem. If you get an answer could you send my a reply.

[email protected]

Thank you


12:57PM | 03/01/03
Member Since: 11/26/02
33 lifetime posts
I am still working on mine. The problem for me is that my plug is 3-3/8" for the outer dimension, and I haven't found a replacement yet. I wouldn't mind breaking it out if I had a replacement, so until them I'm being careful.

I found a good discussion on this topic at DIY (,2021,3_175033,FF.html. Hope this helps.

Mark K

02:30PM | 03/15/03
Member Since: 08/12/02
3 lifetime posts
gtillotson, your a life saver, i had a problem with a plug on a cast iron main 4 inch drain and I did what DIY suggested, by drilling some holes, and using a jigsaw with a metal blade...lots of work but I finally got the damn thing out...thanks to you my new laundry room is still on schedule..=)


05:20AM | 03/18/03
Member Since: 11/26/02
33 lifetime posts
I finally got around to removing mine, and here is what I did: I drilled four holes, one at each corner of the plug "nut". I let the water drain out, then I cut out the nut using a metal cut-off wheel (Rotozip).

After this, I used the cut-off wheel to slice away portions of the cap until I could get near the inner ring. I then cut slots right up to the edge of the cast iron pipe.

From there I used a hacksaw to cut vertically from the inside out to the edge of the threads. You can feel and hear when you start grazing the cast iron, so cutting by hand this way is safe. Once I'd cut through the plug in about four places, I tapped the chunks out with a cold chisel.

I don't have a replacement plug yet for the odd 3-3/8" cleanout, but I'll go hunting today. I was amazed at the amount of crud in there -- a big plug of junk and sediment lining the walls of the cleanout.


07:20AM | 03/21/03
Member Since: 02/28/03
3 lifetime posts
Well, it took a 65 year old little man to show me. "It's all about leverage, Kid," he told me. Try using an extention on your pipe wrench. I used a 4 ft. galvanized fence post. All it took was a couple of bumps, and it was ready to move.


10:03AM | 03/21/03
Member Since: 11/26/02
33 lifetime posts
This is good to hear. I was thinking of this, but drum trap was in a tight spot and I was concerned that too much torque would damage the connecting pipes. Next time I'll remember to look for a fence post.


12:44PM | 10/15/12
Member Since: 10/15/12
1 lifetime posts
I tried some of the others, including heat and rust removor oils, with no result, but this one using leverage worked. I have been living in this house for 28 years and it had never been off, I don't know how long before then.


08:33PM | 05/27/13
I just smacked around the perimeter of the cap with a hammer and a large pipe wrench removed mine no problem.
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