Upper Peninsula Rubber Company manufactures the rubber element of a pipe joint repair system for rehabilitating leaking joints in concrete, iron, steel, vitrified clay, PVC, and HDPE pipe. Internal Sealing Diaphragms incorporate an EPDM rubber gasket that is centered over a joint and fastened to the interior wall of circular pipe with expandable stainless steel clamps. The resultant repair seals the pipe against infiltration and exfiltration with minimal flow impedance.