Many ELM shower bases installed in homes in the '70s are leaking. While replacement of the entire base is the best solution, EL Mustee has come up with a repair. The original drain is swedged into the shower base. Most plumbers will tell you the drain cannot be removed - that the entire base must be replaced. This is not so. If you have access to the drain from below, you will see a metal band around the top of the drain, up against the fiberglass shower base (viewed from below). Cut the band with a Dremel tool, being careful not to slip and cut the base. Cutting the band will release the entire drain and bell housing. Purchase replacement part EL Mustee (ELM) 42.317A, which can be screwed or bolted into place, making the new drain a permanent repair, saving ripping out the old base. To identify the base, carefully examine the metal plate which lays atop the shower base drain. It has an "ELM" logo on it. This stands for EL Mustee. A phone call to EL Mustee, in Illinois, may prove very helpful. I was received with great courtesy and an articulate response.