Step 3 · Clean and Prepare Drain Pipe
Once the flange is removed, thoroughly clean the top edge and the outer surface of the cast iron drain pipe where the new coupling will sit. Use a wire brush to remove any rust, residue, and remaining bits of lead or oakum. The surface must be clean and relatively smooth to ensure a watertight seal with the new flexible coupling. Use a shop vacuum to clean up all debris from the surrounding area.