Abstract: A hydraulic system for operating dock levelers, vehicle restraints, and other types of loading dock equipment includes one or more features that prolong the life of the hydraulic fluid. A hydraulic reservoir with a desiccant filled breather cap or a hermetically sealed pliable reservoir minimizes the hydraulic fluid's exposure to condensation and atmospheric moisture. The system can be used for prolonging the life of both biodegradable and- non-biodegradable hydraulic fluids. In some embodiments, the system includes an acceptably biodegradable fluid having a combination of properties that makes the fluid particularly suitable for loading dock equipment.