A sealing assembly has an expansion band having an arcuate band portion and a pair of threaded end portions formed at opposing ends of the arcuate band, in which the arcuate band and threaded end portions are monolithically formed as a single piece. Fixed within respective threaded end portions are a pair of oppositely threaded nuts adapted to receive a bolt having correspondingly oppositely threaded ends. Rotation of the bolt causes the threaded end portions to be simultaneously driven apart or drawn toward one another (depending on the rotation direction of the bolt) to thereby expand or contract the overall outer profile of the arcuate band portion. The monolithically formed expansion band may be made of an inexpensive, non-rusting material such as nylon 66, and glass fibers and/or additives may be employed to impart strength and flexibility.