A deactivating hydraulic valve mechanism includes a hydraulic element assembly disposed within a pin housing slidably disposed within a bore in a body. A transverse bore in the pin housing contains selectively-retractable locking pins that engage a groove in the body to selectively lock together the body and the pin housing. A lost motion spring is disposed in an annular chamber between the body and the pin housing. An oil passage from an engine gallery to the hydraulic element assembly includes an axial component and bypasses the lost motion chamber. A ring holds the lifter assembly together and also sets mechanical lash. The ring may be provided as a standard-thickness ring and a shim selected to provided a predetermined amount of mechanical lash in the assembled mechanism to ensure facile engagement and disengagement of the locking pins in the body.