How To Replace Garbage Disposal Blades

It's something of a misconception that a garbage disposal has blades. If you look into the mouth of your disposal, you'll see two oblong impellers attached to the rotor plate, which is the part that spins, but the impellers aren't sharp. Their purpose is to fling food toward the shredder ring on the side of the canister where the actual food mashing takes place.

The impellers are designed to spin freely — the better to fling food — but they sometimes freeze up or come loose. When they freeze, you can use a simple trick to free them, but a garbage disposal with loose mounting screws on the impeller will rattle loudly and will likely need to be replaced.

Even though the impellers aren't actually blades, it's fair to identify them as such for the purpose of repair. When they freeze up, the garbage disposal won't work properly, food will be poorly ground, and the disposal will probably clog up frequently.

You can test for frozen impeller blades by turning off the disposal and testing the movement with a wooden implement, such as a broom handle, never your fingers.

If the impellers are stuck, try to loosen them by doing the following:

1. Toss steak or pork chop bones in the disposal and grinding them completely. Despite the fact that this makes a horrendous noise, experts say it's completely safe. If you're squeamish about grinding bones, you can probably get the same results by grinding ice cubes.
2. Look into the mouth of the disposal and you may find a piece of metal, such as a coin, that's making the rattling sound. Remove it with tongs or pliers; not with your fingers.
3. Repeat this process if it does not work — it may work the second time around.

When the mounting bolts on the impeller plate are loose, you'll hear a rattling sound, but when you look into the disposal, you won't see any foreign objects. Test the impellers by pushing against them with a wooden implement. They should spin freely, but they shouldn't have any back and forth movement.

If the impellers are loose, or they're stuck and you can't get them to spin freely, your best bet is to simply replace the disposal. The impellers are often fastened with rivets and are not designed for easy replacement. Removing an old disposal and installing a new one is a good DIY project that takes just a couple of hours.

1. Turn the garbage disposal off and disconnect it from power, either by unplugging it or turning off the breaker of the circuit feeding the disposal. If the unit is hardwired, remove the electrical terminal plate and disconnect the wires. You don't have to do this if the unit has a plug.
2. Disconnect the P-trap — make sure to put a bucket under the sink because it will be full of water. If you have a dishwasher, loosen the clamp holding the drain hose and remove the hose.
3. Remove the disposal by inserting a standard screwdriver into one of the loops on the mounting ring under the sink and rotating the ring counterclockwise. Make sure the disposal is supported because it can drop suddenly once you loosen the ring. Some disposals are removed by grasping them with two hands and turning them counterclockwise by 1/4 turn to free it from the mounting bracket.