Embodiments of translating nut mechanism having enhanced lubrication features are provided, as are embodiments of variable bleed valve systems employing translating nut mechanism in the form of bidirectional stop mechanisms. In one embodiment, the translating nut mechanism comprises a housing containing a pool of grease or another lubricant. A screw shaft is mounted in the housing for rotation about a working axis. A translating nut is threadably mounted to the screw shaft and moves linearly along the working axis with rotation of the screw shaft. A first lubricant distribution feature, such as a grease paddle, projects from the translating nut into the lubricant pool. The first lubricant distribution feature moves through the lubricant pool to distribute lubricant within the translating nut mechanism as the translating nut moves along the working axis.