Abstract: This invention concerns a hydro static wrench for removably connecting to a socket wrench for removably engaging and removably installing a hydrostatic relief valve having a cap portion, an axial cap projection, and radial cap extensions. The hydro static wrench comprises a sleeve comprising a body portion, at least one opposing arcuate sidewall, and at least one opposing slotted sidewall. The body portion axially extends along a first axis and has a top planar portion and a bottom planar portion located opposite and parallel the top planar portion. The top planar portion has a projected polygonal aperture for removably engaging the socket wrench and the bottom planar portion has a polygonal aperture for removably engaging the axial cap projection.