How to Change the Lavatory Drains to Spring Pop-up Drains

Locate the P-trap under the lavatory sink. The P-trap is a U-shaped plumbing pipe underneath the sink. Place a small bucket or bowl underneath the trap to catch any water.

Turn the top nut on the P-trap clockwise with your hand or an adjustable pliers to loosen it, and move it to the side -- you don't need to take the entire P-trap off. With the P-trap unscrewed, the tailpiece of the current assembly is exposed.

Loosen the tailpiece connected to the upper drain pipe with the pliers. Then loosen the upper drain pipe from the drain. Now the old piping is loose enough to remove.

Hold down the old strainer at the bottom of the sink bowl with your hands to keep it from spinning as another person underneath the sink loosens the strainer nut with the pliers. Pull the assembly out from underneath the drain, and pull the strainer out of the sink. The old assembly is now removed.

Roll plumber's putty into a coil with your hands. Wrap the coil underneath the rim of the new strainer. Push the new strainer into the sink drain.

Get under the sink and screw the bottom of the pop-up assembly to the bottom of the strainer. Push the nut on the pop-up assembly up around the top of the assembly and screw it until tight.

Remove the excess putty from around the drain with your fingers.

Drop the new pop-up stopper into the drain. Make sure the flange on the end of the stopper is pointed toward the wall as you drop it in.

Pull out the old pull rod from behind the faucet on top of the sink. Stick in the new pull rod into the hole behind the faucet.

Insert the pull rod into the holes on the strap. The strap is lined with holes and connects the pop-up assembly to the pull rod.

Insert the end of the new ball-joint rod into the open joint on the pop-up assembly underneath the sink. Turn the nut on the ball-joint rod clockwise until tight.

Slip one end of the clip onto the ball-joint rod. Line the ball-joint rod up with the strap; insert the rod into the strap's bottom second, third or fourth hole.

Wrap the free side of the clip on the ball-joint rod around to the backside of the strap. Push the portion of the ball-joint rod sticking out of the strap into the free side of the clip to hold it in place.

Pull the strap up and down to adjust the height so the strap lines up with the ball-joint assembly. Then tighten the set screw to keep the strap at the required height.

Connect the P-trap plumbing pipe to the pop-up assembly. Tighten it to the assembly with a nut and pliers.