Disclosed herein are active hydraulic cylinders for use in active vehicle suspension systems, and methods for assembling active hydraulic cylinders for use in an active vehicle suspension system. In particular, in certain embodiments a manifold may encircle a portion of an outer tube of a twin tube assembly. The manifold may mechanically and fluidly couple a pump assembly to the twin tube assembly. In certain embodiments, the manifold may be welded onto the outer tube.