A system for greasing a valve is provided. The system comprises a main valve connected to a compressed fluid source, a grease supply system, a main chamber, a left head assembly, a right head assembly, and a grease supply line in communication with the valve. The main chamber includes a piston that is slidable from a first end to a second end of the main chamber. In the first position, the main valve injects fluid into the first end of the main chamber, thereby charging the left head assembly with grease and simultaneously discharging grease from the right head assembly into the grease supply line. In the second position, the main valve injects fluid into the second end of the main chamber, thereby charging the right head assembly with grease and simultaneously discharging grease from the left head assembly into the grease supply line.