An improved hydraulic lash adjuster including a cup-shaped adjuster body, and a plunger assembly disposed within the adjuster body. The plunger assembly includes a stepped axial bore extending from a body inner end to a central oil passage opening onto a hemispherical pivot head. A check valve cartridge sub-assembly is disposed against the step, defining a low-pressure oil chamber in the axial bore. A lash adjustment spring is disposed against the cartridge sub-assembly in a high-pressure chamber formed between the sub-assembly and the adjuster body. The cartridge sub-assembly may be used in other hydraulic lash adjusters such as are incorporated in hydraulic valve lifters.