An electric submersible pump (ESP) seal section assembly. The assembly comprises a seal section filled with dielectric oil; a coupling body partially inserted into the seal section, and a coupling body, wherein the coupling body is substantially cylindrical and has a first outside diameter at an upper end of the coupling body, has a second outside diameter smaller than the first diameter below the first outside diameter, has a circumferential tapered shoulder between the portion of the coupling body having the first diameter and the portion of the coupling body having the second diameter; a service-less flange coupled to the seal section, wherein the service-less flange defines a circumferential opening having a circumferential tapered shoulder on an upper edge that contacts the circumferential tapered shoulder of the coupling body.