A lubrication system for a hydraulic hammer is disclosed. The lubrication system includes a housing having a first chamber, and a control valve, disposed proximal to a first end of the first chamber, moveable from a closed position to an open position. A piston is received within the first chamber and moveable between a first position and a second position. The piston includes a first end having a cavity, and a second end facing towards a second chamber, which receives hydraulic fluid therein. In the second position, when the first chamber is filled with air in the first position of the piston, the cavity defined at the first end of the piston maintains pressure of the air less than a biasing force of a resilient member that keeps the control valve in the closed position.