Lionel 681-120 Rear Bearing - The 681-120 rear motor bearing is used in the motor housing of Lionel's later slant mounted 681, 726 and 2020 motors. It is the bearing located just beneath the armature. This later bearing bushing eliminated the recess or indent where the bearing race and loose ball bearings once fit. Original bearings such as these are made of Oilite® bearing material, a powdered bronze formed under pressure and impregnated with oil. These bearings should be installed using a press, as tapping them in with a hammer could fracture the bearing causing it to fail. Never use grease around these bearing types as grease will block the pores of the Oilite® material. Many parts dealers try and substitute machined brass rod for these bearings as it is cheaper, and while they will work, they need contant oiling as brass has no pores to trap and hold the oil.