An annular isolator (68, 70) is disposed in an open ended bore (66) of a support body (58) and surrounds an end fitting (26, 28) for attenuating vibrations therebetween. A cap (74) is disposed on the support body (58) to close the open ended bore (66). An inflexible compression ring (76) is sandwiched axially between the isolator (68, 70) and the cap (74) and in abutting engagement with a stop (78) to limit compression of the isolator (68, 70) from the cap (74). The compression ring (76) is inserted into the bore (66) prior to molding the cap (74) to limit compression of the isolator (68, 70) during fabrication.