Step 5 · Install New Basket Strainer
Take a generous amount of fresh plumber's putty and knead it in your hands to warm it up. Roll it into a uniform, snake-like rope about 1/4-inch thick. Wrap this putty rope around the underside of the new basket strainer's flange. From above the sink, press the strainer firmly down into the clean drain hole. The putty should squeeze out evenly around the entire perimeter. From underneath the sink, slide the rubber gasket up against the sink bottom, followed by the fiber or cardboard friction washer, and finally the large metal locknut. Hand-tighten the locknut as much as possible. To finish, use channel-lock pliers or a dedicated strainer locknut wrench to give the locknut a final half-turn. To prevent the strainer from spinning while you tighten, have a helper hold it steady from above by inserting the handles of pliers or a screwdriver into the crossbars. Wipe away the excess putty that squeezed out on the top side of the sink with your finger or a cloth.