Access Plug to drain frozen

Hi, I have a plumbing problem, but before I can begin to figure out what it is I need access to the drain. But the large 4" plug is frozen on.

It is an old cast iron plug with a square knob. I've tried spraying it with PB Blaster for 2 days, and tapped it 100 times, and put a large wrench on it with a hug pipe for leverage. I tried working it both direcitons....

All I've managed to do is crack the knob on one side and distort it on the other. The knob seems to be twisting but the threads aren't! Now I can't get a grip to turn it at all.

My thought is to drill two holes equidistant from the center and try to fit some kind of thing to turn it? But what would I use? I know cast iron is soft and I could probably just drill out the whole thing. But I'd need advice on how to do that too, and how to replug the thing once I was done?

Any suggestions greatly appreciated. Please see the picture.

Use a real sharp chisel and cut it out. That's not a very heavy brass plug.

Go buy another clean out plug first........

Have you tried using a plumber's torch? I'd wipe off the PB Blaster first, since it might be flammable.

thegallery said:

Hi, I have a plumbing problem, but before I can begin to figure out what it is I need access to the drain. But the large 4" plug is frozen on.

It is an old cast iron plug with a square knob. I've tried spraying it with PB Blaster for 2 days, and tapped it 100 times, and put a large wrench on it with a hug pipe for leverage. I tried working it both direcitons....

All I've managed to do is crack the knob on one side and distort it on the other. The knob seems to be twisting but the threads aren't! Now I can't get a grip to turn it at all.

My thought is to drill two holes equidistant from the center and try to fit some kind of thing to turn it? But what would I use? I know cast iron is soft and I could probably just drill out the whole thing. But I'd need advice on how to do that too, and how to replug the thing once I was done?

Any suggestions greatly appreciated. Please see the picture.

Click to expand...

cut it out with a reciprocating saw, or chisel it out with a hammer and cold chisel (start chiseling at the base of the square head and work your way around. Once you have the square head portion out work your way outward, hitting it in a counterclockwise direction. Eventually the plug will come out. It is brass and not as hard as it sounds. When finished clean the threads and replace with a plastic plug)

If there are any threads sticking out you can try taking a heavy flat head screwdriver and try wacking the cover working the cover backwards around the C/O. Many times this will loosen it up. If not chizel it out being careful not to harm the female threads and get a new cover. Don't spend a lot of time trying to get the old one off a new cover is only a $5.00 -$10.00

plug

Cast iron is not soft. That is a brass plug, and as my father used to say, "It is a good thing they make them out of thin metal, because you almost always have to cut them out." There are a lot of ways to remove it, but it is hard to describe them without you misreading the message and possibly breaking the tee the plug is into.

Thanks for all the advice. I ended up drilling a couple of large holes in the plug and using a reciprocating saw to cut close to the edge in a couple of places. I then was able to hammer on the edge of some threads that were sticking out where I cut the face plate pretty thin. I hammered using the large screwdriver, and that having that face plate cut allowed the threads to bucking inward and the plug came right out.

The female threads seem pretty corroded or at least gunk-ed up with a deposit as hard as metal. But I tried a new plastic plug with some Teflon tape and its sealing fine, (even though it only spun in a turn or two.) We filled up the tub and sinks and let them go and flushed the toilets all at once. It did fill up the pipe and we did see a couple of drops at the access plug, but it quickly drained through the system.

So, now I need to tackle the problem that is causing the drain to gurgle and back up! This access point is right where the main drain goes into the ground in the basement, and about 5' further along is the deep sink drain which joins into it this main drain. The deep sink's drain has gotten clogged with lint from the washer for many years. We just pull some out of the plug area every now and then, and never got around to putting a strainer on the washer out pipe.

I'm hoping the symptoms in my system are just from the the lint build up all the way down to the main drain, an not a root or something serious. I snaked about 12' of line into the main drain and found no blockages. I then filled up and plunged the deep sink about 5 times and it seems to be flowing find now too. No more gurgling sounds in the rest of the house at least.

So I'll keep an eye on it, and if I do have to call a pro in because I find I have a block further down, at least the access plug will be easy for him to get to!

Also, I'm going to cut the old trap out of the deep sink so I can snake it from there. (It's all one piece.)I'll then replace it...

Thanks again for advice on the plug...

If you remove the C/O cap and take a 3/4 or 1/2" fitting brush you can remove lots of the junk preventing the cap from going in farther. Use a awl to remove chunks stuck in the threads

Yeah, I tried to hammer it a bit with a screwdriver, but I was frightened of damaging the threads. As it seems to be sealing pretty good I'm inclined to leave it.

Everything seemed fine last night and this morning; no gurgling. This really could have all come from the lint clogging the entire drain from the deep sink. Meanwhile someone recommended a pro and I'll talk to him today, and possibly bring him out mainly just to double check all is in order.

I wonder if there is a way to 'test' the drain, like the flow rate, or if there is a blockage. Again, right now all is OK, but it's just me in the house. When my roommates are back and one is taking a shower while one is flushing the toilet while the washer is going.... well we could be back to square one.

Anyway, I'm very pleased to have at least removed the C/O plug, and I couldn't have done it without the responses here.

If you're real lucky, the pro you call might have or know where to get, a 4" tap or thread chaser to clean up those ratty threads.