The Dead Weight Hydraulic Assembly provides a source of constant Hydraulic pressure in one compact unit. It consists of a water reservoir, piston and cylinder, dead weight, delivery pressure gauge, two check valves and a bleeder valve. When attached to a standard Series 300 Filter Press it delivers 100 psig pressure to the filter press cell as specified in the American Petroleum Institute, “API Recommended Practice 13B-1 and 13B-2”.