A sink stopper stuck in the open position is annoying, but at least you can still use the sink. A drain stopper stuck in the partially closed or closed position is another thing.
If you're wondering why you can't open the drain stopper with the lift rod, the answer is simple: something has come unhooked.
The problem may have been initiated by gunk in the drain, but that often leads to something coming apart or breaking. You can definitely fix a broken sink stopper yourself, as long as you're willing to crawl under the sink. The only tool you'll likely need is a pair of locking pliers. Oh... and a flashlight.
Dealing With a Drain Stopper Stuck Open
A sink stopper mechanism isn't difficult to understand. When you push or pull on the lift rod, it activates a lever the extends through the drain tailpiece. The lever hooks onto the stopper through a hole or hook on the bottom of a long plastic flange that's attached to the stopper. It moves the stopper in the opposite direction to the lift rod.
The lift rod connects to the lever by means of an adjustable metal strip called a clevis. Sometimes, the problem is as simple as the clevis screw being loose. If so, you'll probably need to tighten it with the pliers, because finger-tight is seldom good enough. The clevis screw is up behind the sink bowl, though, making it a challenge to see and reach, which is why you need a flashlight.
Inside the tailpiece, the thin plastic strip at the base of the stopper flange may have broken. When this happens, the lever will push the stopper up, but it won't pull it down, leaving the stopper stuck in the open position. You have to disassemble the stopper mechanism to fix this.
How to Service a Lever-Style Sink Stopper
After you've cleared out the sink cabinet to give yourself room to work, crawl inside the cabinet face up and follow the pivot rod to the tailpiece, where you'll find a ribbed nut. You can loosen the nut with your fingers, and after you remove it, you'll be able to pull out the lever. Before you do, though, you'll have to disconnect the pivot from the clevis. To do this, you first have to squeeze the metal clip holding it and slide it off.
Once you remove the lever, you can pull the stopper out of the drain and replace it if it's broken. When the stopper is out, you have a golden opportunity to give the drain a deep cleaning. It may even be worth the time it takes to remove the P-trap so you can do a thorough job.
To reassemble the mechanism, drop the stopper into the drain, insert the lever into the tailpiece and hook it into the hole at the bottom of the flange. Test the connection by moving the lever up and down, making sure the stopper responds. Screw the lever nut back onto the tailpiece, tighten it finger-tight, reconnect the lever to the clevis and tighten the clevis nut with pliers.
Read more: How Do I Reconnect the Sink Stopper?
Servicing a Push-Button Sink Plug
If your sink has the type of stopper that you push to close and push again to open, you don't have to worry about a lever mechanism — and you can make the repair without going under the sink. When you have a push button sink plug stuck in the open position, it's usually because something is interfering with the spring.
To disassemble the plug, unscrew it by turning it counterclockwise. Depending on the model, you may have to hold the flange steady with pliers while you turn the actual stopper. Once it comes apart, you can either readjust the spring or replace the stopper.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.