Disposal Jammed
Updated February 20, 2026
Motor hums but nothing grinds? Something is wedged between the impeller and shred ring. Ten-minute fix with a 1/4-inch Allen wrench.
Overview
Humming means the motor has power and is trying to spin, but something is physically blocking the grinding plate. Different from a disposal that will not turn on at all (that is usually electrical). Every disposal made in the last 30 years has a hex socket on the bottom for exactly this situation. 1/4-inch Allen wrench, work it back and forth, dislodge what is stuck. Simple, safe, no plumber needed.
Symptoms
- Hums loudly but nothing grinds -- motor running, flywheel stuck
- Brief hum then silence -- thermal overload tripped to protect the motor
- Water backing up because the disposal cannot process waste
- Metallic scraping or grinding sound before it locked up -- hard object like a utensil or bone
- Worked fine until a specific item went in (you may know exactly what caused it)
Common Causes
- Hard objects between the impeller and shred ring -- bones, fruit pits, dropped utensils, bottle caps. They wedge into the gap and stop rotation.
- Fibrous foods wrapped around the impellers -- celery, corn husks, artichoke leaves, onion skins. Long fibers wind like string and create enough drag to stall the motor.
- Grease and food buildup -- coats the grind chamber over time. Combined with a slightly hard item, the buildup is enough to cause a jam.
- Foreign non-food objects -- rubber bands, twist ties, produce stickers, glass, small plastic items. Wedge tightly and harder to clear than food.
- Running without water -- water lubricates and flushes. Dry operation packs food tight in the chamber.
What You'll Need
How to Fix It
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Turn Off the Disposal and Disconnect Power
Switch off. Then unplug from the outlet under the sink or kill the breaker. Never put your hand inside a powered disposal -- faulty switch or accidental bump could activate the motor.
Warning: Do not reach in with your fingers even when unplugged. The impellers are metal and can cause serious cuts if the flywheel suddenly frees while your hand is inside. -
Use the Allen Wrench to Free the Flywheel
Bottom center of the unit: hex hole (1/4-inch on most). Insert the Allen wrench and work it back and forth. Resistance where the object is jammed. Keep working until the flywheel moves freely in both directions. Primary fix, clears the jam in most cases.
Tip: No Allen wrench? Wooden broom handle from the top, placed against an impeller arm to push and rotate. Works but gives less leverage than the wrench from below. -
Remove the Obstruction
Flywheel free? Flashlight into the chamber from above. Find and remove whatever caused the jam -- tongs, needle-nose pliers, not your fingers. Small bones, fruit pits, glass, utensil handles, fibrous wads. Get all loose debris out.
Tip: Cannot see it? Pour a little water in and change the flashlight angle. The object may be wedged under the impeller plate, hard to spot from directly above. -
Reset the Thermal Overload
Red reset button on the bottom, near the Allen wrench hole. When the motor stalls, this thermal overload trips automatically. Press firmly -- feel and hear a click. No click? It has not tripped and is already reset.
Tip: Left the switch on while it was humming? Wait at least 5 minutes before resetting to let the motor cool. Running a stalled motor continuously burns it out. -
Test the Disposal
Power back on, cold water running, flip the switch. Should spin up normally. Run 15-20 seconds to flush debris. Hums but does not spin? Jam is not fully cleared -- repeat the Allen wrench. No hum at all? Check the reset button and breaker.
Warning: No response after clearing and resetting? Motor may have burned out from running too long in a jammed state. Burned motor means replacement. -
Clean the Disposal After Clearing the Jam
Running again? Clean it. Handful of ice cubes and half cup rock salt, run with cold water 30 seconds. Ice and salt scour the grind chamber and impellers. Follow with half a lemon or lime to deodorize. Safe for regular maintenance.
Tip: Ice-and-salt cleaning once a month. Keeps the disposal clean and reduces future jams from grease and buildup.
When to Call a Pro
Call a plumber if the disposal is completely dead after resetting (may be electrical or burned motor), if the flywheel will not budge even with sustained Allen wrench effort, if broken glass or sharp metal is inside and you cannot safely remove it, or if the unit leaks from the bottom (failed internal seal, needs replacement). Burned motor? Replacing the whole unit is almost always more cost-effective than repair.
Prevention Tips
- Cold water running before, during, and 15 seconds after. Cold solidifies grease so it gets chopped up instead of coating the drain.
- Feed small amounts, not a stuffed chamber. Overloading is a top cause of jams.
- No bones, fruit pits, corn cobs, or shellfish shells. Too hard for most residential units.
- No fibrous foods -- celery, corn husks, artichoke leaves, onion skins. Fibers wrap around the impellers.
- No grease or cooking oil. Coats the grind chamber and makes food stick instead of flushing through.
- Keep the Allen wrench attached to the unit with a zip tie or magnet. Always accessible when you need it.