Abstract: A replaceable mounting ring is disclosed for use with a water closet coupling which is interposed between a water closet drain and a sewer pipe. The mounting ring fits on a channel in a flange near the inlet end of the water closet coupling. The mounting ring comprises two arcuate members, each having a U-shaped cross section formed by a base and a leg on each side of the base, with the base having a lower surface between the two legs. A corresponding end of each arcuate member has an extension from the lower surface of its base of a size which allows the extension to engage the lower surface of the base of the opposite end of the other arcuate member. These extensions enable the ends of the arcuate members to form a mounting ring having a U-shaped cross section. At least one of these extensions can be fastened to the other arcuate member by a pivot joint which allows that arcuate member to be rotated through an opening in the leg on the outside of the other arcuate member.