A system and method is provided for hydraulically presetting a metal-to-metal seal, which may be installed in an annular space between wellhead components. A hydraulic running tool may be landed on a first wellhead component and coupled to a second wellhead component, for example, via a hydraulic or mechanical coupling assembly. Fluid pressure may then be applied to the hydraulic running tool to move the components axially together, thereby setting the metal-to-metal seal (i.e., axially compressing and radially expanding the seal). A coupling may secure the wellhead components in place relative to one another, while fluid pressure is being applied so that the metal-to-metal seal remains in the set position after the hydraulic tool is removed.