Turn Off the Power and Remove Drain Lines

The first step is to look under the sink to make sure a disposal system will fit. Then, at the breaker, turn the power off.

Remove the existing drain lines. Place a rag in the main drain to prevent leakage.

Next, loosen the large nut on the base of the sink flange, then let it drop down.

Push the strainer body through the sink and remove.

Remove the Putty and Loosen the Screws

Carefully use the screwdriver to remove all the putty from around the sink opening. Use a rag to make sure none of the old putty is left and that the sink opening is clean.

Turn the mounting assembly over, then using a screwdriver and your fingers to loosen all the mounting screws until you have access to the snap ring.

Remove the Snap Ring

Using a screwdriver, pry the snap ring off the sink flange. The mounting assembly will now come apart.

Separate all the parts being careful not to damage the fiber gasket.

Apply Putty

Roll a large amount of plumber's putty around the sink opening, then press it firmly into place.

Slip the fiber gasket and metal backup ring over the sink flange.

Slip the Mounting Ring Over the Flange

Hold the fiber gasket and backup ring in place while slipping the mounting ring over the sink flange so it seats against the backup ring.

Place a wide rubber band around the flange to hold the parts in place. Be sure that it's above the snap ring groove.