Quick Answer:
If the lift rod turns but the stopper just spins in place, the pivot ball and the pivot nut under the sink are often loose or disconnected. Check the pivot ball connection, tighten the nut a small amount, and inspect for stripped or worn parts. If parts are damaged, replace the pivot assembly or the pop-up.
Why This Happens
The lift rod moves a pivot rod that fits into a pivot ball on the drain assembly. If the pivot ball or the pivot nut is loose, worn, or broken, the top stopper will spin freely instead of moving up and down. Corrosion, plastic parts that have cracked, or stripped threads let the stopper turn without transferring motion to the pivot rod.
Related problems you might also see are Pop-up won’t stay down and Stopper works only sometimes, which often share the same pivot or linkage issues.
Step-by-Step What to Do
1. Prepare the area
- Place a small bucket or towel under the trap to catch water or dropped parts.
- Move toiletries and items from under the sink so you can work comfortably.
- Put on gloves and eye protection if you expect dirt or debris.
2. Inspect the pivot ball and nut under the sink
- Locate the horizontal pivot rod that goes into the drain and the nut that holds it near the pivot ball.
- Check for visible looseness: if the nut is loose it will allow the top stopper to spin without moving the pivot rod.
- Look for cracked plastic around the pivot ball, a missing retaining clip, or damaged threads on the rod or nut.
3. Remove the stopper if needed
- Lift the stopper and try to pull it straight up; many stoppers lift out once the pivot rod is unhooked.
- If the pivot nut prevents removal, unscrew the nut partway, support the stopper from above, and rotate the lift rod to free the pivot rod from the ball.
- Keep track of any small washers or clips.
4. Tighten or replace worn parts
- If the pivot nut is just loose, tighten it until the pivot rod moves the stopper correctly. Tighten by hand first, then a small quarter-turn with pliers—do this carefully.
- If threads are stripped, the pivot ball or nut is cracked, or the pivot rod is bent, replace the damaged part or the whole pop-up assembly.
- Reassemble in the reverse order, test the lift rod, and adjust the pivot nut slightly if necessary for smooth movement.
5. Test thoroughly
- Operate the lift rod several times to confirm the stopper moves up and down without spinning.
- Check for leaks around the pivot nut and the drain after reassembly.
What Not to Do
- Do not overtighten the pivot nut; it can crack plastic parts or seize the joint.
- Don’t force a stuck pivot rod with excessive bending—forcing can break the rod or damage the drain tailpiece.
- Avoid using chemical drain cleaners to loosen pivot parts; they won’t fix mechanical linkage and can harm finishes or plastic parts.
When to Call a Professional
- The pivot threads or tailpiece are badly stripped or corroded.
- You cannot access the pivot nut because of tight cabinets or plumbing layout.
- Leaks start after reassembly, or the mechanism still doesn’t work after replacing obvious parts.
- You prefer not to deal with replacing the drain assembly or soldered/metal parts.
Safety Notes
- Always put a bucket under the trap before loosening fittings to catch water and parts.
- Wear gloves and eye protection when working under the sink.
- Avoid chemical cleaners on mechanical parts; use manual cleaning and replacement instead.
- If a part is plastic and cracked, stop tightening and replace it—overtightening can make things worse.
Common Homeowner Questions
- Why does my stopper sometimes spin but sometimes works?
Usually the pivot nut is loose or partially worn; tighten and inspect for intermittent connection or wear. - How can I tell if the pivot ball is stripped?
If the nut turns with no grip on the pivot rod or the stopper spins freely even after tightening, the ball or threads are likely stripped. - Can I replace the pivot nut myself?
Yes—if the tailpiece and pivot rod are accessible and undamaged. Replace the nut or whole pivot assembly if threads are bad; otherwise tighten carefully.