The hardest part of replacing an old garbage disposer is fitting comfortably under the sink.

Step 1: Disconnect the power supply to the old garbage disposer. If the disposer is hard-wired, use the circuit breaker or fuse to turn the power off at the electrical entrance panel. Otherwise, unplug the old cord.

Step 2: Disconnect the drain line from the old disposer. Place a pan or bucket beneath the drain line to catch any excess water and goo. Have plenty of towels to clean up the mess that may ensue.

Step 3: Use a screwdriver or disposer wrench to push the lower mounting ring of the disposer to the left until the disposer falls free from the mounting assembly. Be prepared: The disposer is surprisingly heavy.

Step 4: It is easiest to mount the new disposer to the existing mounting assembly. To install a new mounting assembly, use at least a quarter-pound of non-hardening plumbers putty rolled into a 3/4-inch-thick rope to properly seal the new sink flange to the sink. Set the old disposer on top of the new flange to hold the mounting assembly in place while installing the new disposer.

Step 5: If the disposer was plugged into the wall, use wire nuts and plenty of electrical tape to attach the old electrical cord to the bottom of the new disposer. Do not plug the cord in at this time.

Step 6: Line up the mounting tabs with the lower mounting ring and insert the new disposer into the mounting assembly. Make sure the disposer drain is in the proper position to reattach to the drain line. Use a screwdriver or disposer wrench to turn the lower mounting ring to the right to lock the new disposer securely in place.

Step 7: Reattach the drain line. Do not overtighten or cross thread the coupling nut.

Step 8: Check inside the disposer to make sure nothing has fallen into it during the installation process. Remove any excess putty from around the sink flange and clear away any debris in and around the sink.

Step 9: Complete the installation by connecting the power supply to the new disposer. Run cold water into the disposer and turn the power on to make sure everything is working properly. Check for leaks before shutting the cabinet door on a job well done.

— Have a home improvement question for Fix-It Chick? Email it to Linda Cottin at hardware@sunflower.com.