Abstract: A compression relieve type braking apparatus comprising a slave piston, a master piston, a housing defining a first passageway, and a pressure release mechanism. The first passageway interconnects the master piston and the slave piston. The master piston is responsive to the engine cycle in a manner to move between a first master piston position and a second master piston position. The pressure release means is responsive to positioning of the master piston in a manner to relieve pressure in the first passageway when the matter piston (in moving between the first and second master piston positions) reaches a predetermined relief location. The relief of the pressure acts to cause the exhaust valve to retract.