Two maintenance employees were inspecting the Omega coupling on the high melter pump. During inspection, the employees realized the shaft on the pump was broken rather than the coupling. The maintenance supervisor was going to locate a rebuilt seal assembly for the pump. The employees started removing the seal assembly from the pump. As one of the employees removed the base plate bolts from the pump, the head pressure from the high melter tank pushed the seal assembly out of the pump casing and hot sugar juice sprayed onto the employees causing first and second degree burns to the upper and lower arm, hand and chest areas.