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How Pop-up Drain Stoppers Work

Updated March 20, 2018

Although you may have manual stoppers on your laundry and kitchen sinks, your sink drains and bathtubs probably have pop-up stoppers. These convenient mechanisms usually come as part of a set with a bathroom sink faucet and are standard equipment on most bathtubs. They work by means of a hidden linkage. You can access the one for a sink stopper under the sink and for a bathroom stopper by removing the lever from the tub.

Types of Pop-up Stoppers

Sink and bathtub stoppers are similar, but they have slightly different mechanisms. They both have a metal or plastic stopper with a rubber gasket that seals the drain when it is down, and it connects to the handle or lift rod by means of a lever. The lever of a sink stopper extends out of the pipe leading down from a sink drain, called the tailpiece. In a bathtub, the tailpiece extends through the drainpipe to the front of the tub where it connects to the lever by means of a linkage that fits in the tub's overflow pipe.

How a Sink Stopper Works

The lever that works a sink stopper connects to the drain stopper on one end and to the lift rod on the back of the faucet on the other. The stopper usually has a long plate, and the lever fits through a hook or hole in the plate so that lifting the other end pulls the stopper down while pushing raises it. A plate with a series of evenly-spaced holes called a clevis connects the lever to the lift rod. The clevis screws to the rod, and the lever fits through one of its holes and is held in place by a metal clamp.

How a Tub Stopper Works

The linkage in a bathtub doesn't connect directly to the stopper. Instead, it usually has a weight attached to the end, and lowering the handle drops the weight onto the stopper lever, called the rocker arm, which in turn lifts the stopper and opens the drain. Lifting the handle removes the weight, allowing the stopper to either fall into place by gravity or to be pulled down by a spring. Some tubs stopper linkages have a spring attached to the end instead of a weight, but the action is the same. Lifting the handle opens the drain, and lowering the handle closes it.

Adjusting Pop-up Stoppers

You can usually adjust a sink stopper by crawling under the sink and adjusting the clevis. If the stopper isn't working, the screw holding the clevis to the lift rod is probably loose. To adjust a bathtub stopper, unscrew and remove the handle from the front of the tub, and pull the linkage out of the overflow pipe. If the stopper isn't opening, the linkage likely is too short, and you can lengthen it by screwing the nut on the threaded adjustment rod counterclockwise. Shorten the linkage if the stopper doesn't close.

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About the Author

Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.