How to Replace a Garbage Disposal Mounting Assembly

Step 1: Confirm the mounting assembly is the problem

1. Look under the sink and check whether the disposal body is loose at the sink connection, hanging lower than normal, or able to twist out of position too easily.
2. Inspect the mounting ring, support ring, and sink flange area for cracks, heavy rust, bent tabs, missing hardware, or water leaking from the top of the disposal where it meets the sink.
3. Try tightening the mounting connection if it is only slightly loose. If the ring will not tighten, will not stay locked, or the flange still leaks, the mounting assembly is a good repair target.
4. Unplug the disposal if it has a cord. If it is hardwired, turn off the circuit at the breaker and verify the unit will not run.

If it works: You have clear signs the mount or sink flange has failed, and power to the disposal is off.

If it doesn’t: If the disposal is firmly mounted and the leak is coming from the body, dishwasher hose, or drain pipe instead, fix that issue first rather than replacing the mounting assembly.

Step 2: Support the disposal and disconnect it from the plumbing

1. Place a bucket or pan under the trap and disposal.
2. Support the bottom of the disposal with one hand or a stable support from below so it does not drop when the mount releases.
3. Disconnect the dishwasher drain hose if your setup has one.
4. Loosen the drain connection and remove the discharge tube or trap connection from the disposal.
5. Rotate the disposal off the mounting assembly and lower it carefully out of the cabinet.

If it doesn’t: If the disposal will not rotate free, recheck for a locking ring or tabs that still need to be released and keep supporting the unit while you work.

Step 3: Remove the old mounting assembly from the sink

1. From below the sink, loosen and remove the mounting hardware that clamps the assembly to the sink opening.
2. Push the old sink flange up and out from the top side of the sink.
3. Scrape away all old plumber's putty and residue from the sink opening, then wipe the area clean and dry.
4. Check that the sink opening edge is smooth enough for the new flange to seat flat.

Step 4: Install the new sink flange and mounting assembly

1. Roll a bead of fresh plumber's putty and press it under the lip of the new sink flange.
2. Set the flange into the sink opening from above and press it down evenly.
3. From below, assemble the new mounting parts in the same order as the replacement kit and tighten them evenly so the flange stays centered and snug against the sink.
4. Wipe away excess putty from above the sink once the flange is seated.
5. Make sure the mounting ring is oriented so you can lock the disposal back on without interference from the cabinet or plumbing.

Step 5: Rehang the disposal and reconnect the drain

1. Lift the disposal back into position and lock it onto the new mounting assembly according to the mount design until it is fully engaged.
2. Reconnect the discharge tube, trap connection, and dishwasher hose if present.
3. Tighten all drain connections firmly without overtightening plastic fittings.
4. Restore the disposal to its normal position and confirm it sits level without sagging or twisting.

Step 6: Restore power and verify the repair in real use

1. Remove tools from the cabinet, then restore power by plugging the disposal back in or turning the breaker on.
2. Run water through the sink and watch the sink flange, mounting area, dishwasher hose connection, and drain joints for leaks.
3. With water running, turn the disposal on briefly and listen for normal operation without rattling, shifting, or vibration at the mount.
4. Check again after a few minutes of use to make sure the disposal is still locked tight and the flange area stays dry.

If it works: The disposal runs normally, stays firmly mounted, and the sink flange and drain connections remain dry during use.

If it doesn’t: If you find a small leak at the sink flange, the mount may need to be reseated. If the disposal loosens again, recheck fit and locking engagement or replace the unit if the disposal-side connection is worn.