4 inch drain plug remval

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garbert

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trying to remove a 4 inch brass drain plug with a hex nut from a cast iron septic pipe. I soaked it with pb blaster and tapped on the plug, then put more oil on it. put a 24 inch pipe wrench with a 3 ft. cheater on it and it just rounded off the 2 contact points. house was built in 1952 and dount if it was ever off. the brass and cast look like new. any ideas for my next move? tia
 
Try it both ways, but just load it and tap on both the plug and clean-out T, keeping in mind that cast iron is brittle.
 
Try heating the cast iron with the hottest torch you have. It should break the corrosion and allow you to remove the plug.If that doesn't work, heat the cast iron again and put some dry ice on the plug, the plug will shrink , and the iron will expand , allowing for easy removal. As a last resort, drill the center of the plug with the largest metal drill you have, then with a metal cutting blade in your jig saw, cut from the hole to the edge of the plug, without cutting into the cast iron threads, in three places. then chisel out one of the wedges the rest should come out easy
 
I recently removed a nasty one. Torch heating is the best approach, assuming you haven't destroyed the nut. Be brave .... torch it all around the perimeter then use a cheater bar on a large pipe wrench. Firm pulling is best as opposed to hitting it with a mallet.
 
I hit it with a cold chisel next to the nut and made a hole in the brass. then put the pipe wrench on with the cheater and the plug turned right out. thanks for the help
 
Good deal.
Before you install the replacement plug, clean the threads with a rotary wire brush.

If the replacement is ABS, I use a wrap of teflon tape, and if Metal, the same or PASCO faucet lub.
 
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