To assemble a bath drain, connect the new drain pipe, and screw it in place. Install the drain cover, and pour water into the tub to check for leaks. When replacing an existing drain, unscrew the old drain cover, and remove the old drain along with the overflow drain pipe before fitting the new drain.
Remove all of the plumber’s putty used to seal the tub drain along with the old drain. Remove the rubber gasket beneath the drain shoe without disturbing the shoe. Unscrew the drain couplings, and remove the old drain pipe. Connect the new drain pipe to the outlet pipe, and check for any obstructions along the vent pipe.
Insert a new gasket by squeezing it into one side of the drain and pushing the other side of the gasket in place. Wrap a piece of plumber’s putty beneath the lip of the drain, making sure it reaches all the way around. Screw the drain in place if the outlet is threaded, or connect the drain to the pipe using the accompanying adapters. Apply caulking around the drain, and tighten the pipe connections. Pour water into the drain to check for leaks and to ensure that the drain is installed correctly.