There are several types of bath tub drains. If you have the type has a lever that flips up or down to either hold water or drain the water. Then I would recommend buying the new kit that goes in the drain. This usually comes with a plate and then a long rod connected to a drain plug. When you move the lever up the plug moves up out of the way of the drain. When you move the lever down the plug moves down to block the drain. So, getting the correct distance in the adjustable rod is critical so the drain will drain and stop the water. So buy the kit, hold up the new drain plate, connecting rod, and plug to the tub and estimate the length. Then install the plug down into the drain and attach the plate. Then test it. You may need to take it out to adjust the length up or down.Kohler Drains for an Examplehttp://designerplumbingoutlet.com/koswbadr.html