Replacing a kitchen basket strainer is the best course of action when a kitchen sink basket strainer is leaking. Some may think that tightening a nut will fix the leak but I assure you it will in almost every case make it worse unless the leak is at the tailpiece connection in which case a new tailpiece washer and tightening the nut will repair the leak. In some cases trying to loosen the nut or, tighten it will cause the basket strainer assembly to rotate at the sink connection in which case that will start the basket strainer connection to the sink leaking.How To Replace A Kitchen Basket Strainer

If the basket strainer to the sink connection is leaking replacement is the only option I would recommend. If you attempt to reuse the old basket strainer assembly frequently has corrosion or, old plumber’s putty in the threads, which won’t let you tighten it properly.

To replace a kitchen sink basket strainer you will need plumber’s putty, a pair of channel lock pliers, a flat screwdriver, something to clean the sink with, and a new basket strainer assembly. You may also need a tool such as a hacksaw, which can cut the drain tubing if needed. If your sink is a porous material that can stain from the oils in plumber’s putty I recommend using Hercules Sta-Put Ultra Plumber’s Putty, which will not stain. For basket strainers I am very partial double cup design similar to the Watts # 645 663BN and I like to see a brass nut for the tailpiece connection as well.
Kitchen Basket Strainer
I have a strong dislike for back nut basket strainers that use a large nut to tighten to the sink like the Watts # 647 003 because, the nut with its large surface area has a lot of resistance that makes tightening difficult and the plumber’s putty can very easily get into the threads making it even worse. If the double cup design is not feasible because you require a low profile basket strainer I would suggest the Kohler Duostrainer like the #K-8799 which although is quite expensive offers superior tightening with its jackscrew tightening system. Picking a good strainer, which tightens well to the sink, is essential to having a leak free connection of the basket strainer to the sink. I cannot begin to count the number of back nut basket strainers I have replaced because they were leaking.

To remove the old basket loosen the nut using the channel lock pliers and if it spins the whole drain without loosening you can cut the nut with the hacksaw or use a screw driver to pop the nut off by prying. They are frequently made of zinc and break easily. Once the nut is off you can lift the strainer out of the sink drain. Clean all the old plumber’s putty from the sink both on top and underneath. Sometimes scraping with a screwdriver works well as does Scotchbrite abrasive pads. Make sure whatever you clean the sink with will not damage the sink finish.

Take out the new basket strainer and disassemble all the parts. Roll out a long snake like bead of plumber’s putty and put it under the flange of the basket strainer where it goes against the sink. Go under the sink and put on the rubber gasket, the cardboard friction washer, then and the cup if you use the double cup type basket strainer or the metal washer if you use the Duostrainer. Then put on the nut and tighten and tighten the nut. If you use the duo strainer after the nut is snugged tight, tighten the jackscrews in alternating fashion until the strainer is tight. Trim the tailpiece as needed replace the tailpiece washer, put the tailpiece in place and tighten the connection on the basket strainer first then tighten the slip joint nut on the bottom of the tailpiece. Cleanup the oily finger prints from the plumber’ putty and test for leaks. Enjoy your leak free basket strainer.