How to Get Sewer Drain Caps Off
The main sewer drain is located in different places in different homes. The drain usually has a cap that screws into the top of the drain entrance. A sewer drain cap has a nut welded to the center that allows for its removal. You may need to remove the cap to resolve a plumbing problem, and it may be stuck from years of non-use. You can remove a sewer drain cap with a moderate amount of effort.
Tighten a pipe wrench around the nut at the center of the sewer drain cap. Turn the nut counterclockwise to loosen the cap from the threads at the top of the drain.
Spray the edges of the drain cap with a penetrating catalyst if you could not loosen it. A penetrating catalyst is a product that helps loosen threaded items that are stuck. Spray a liberal amount of the catalyst around the threads of the cap and let it soak for 10 minutes.
Tap the sides of the nut in the center of the cap gently with a hammer to help loosen it. Use the pipe wrench again and attempt to turn the nut counterclockwise. Apply more penetrating catalyst and tap the nut with the hammer. Eventually you will be able to loosen the cap and remove it by hand.