Grease lubrication is used in many locations where it is difficult to keep lube oil at the bear-ing surface. The grease is applied either through grease cups or grease fittings.

Grease Cup Lubrication

Dirt in lube oil will generally settle out, but dirt in grease will remain mixed within the grease and will become abrasive. For this reason, you must be particularly careful to prevent contamina-tion, especially where grease cups are used. Before you open the container, carefully remove all dirt from the exterior. Do NOT allow any dirt to enter either the opening or the grease cups. You should frequently empty, clean, and refill the cups with fresh grease.

Pressure Greasing

Pressure fittings provide an easy means for lubricating numerous low-speed, lightly loaded, or widely separated bearings. They are not, however, good for use on electric generators and motors, as pressure fittings used on these units may force grease out of the bearing and onto the windings. Pressure fittings are similar to those on an automobile where grease guns are used for lubrication. You must use only one type of grease to fill a grease gun. You should mark the grease gun to identify the type of grease it contains so that you will not use the wrong lubricant. Before using the grease gun, you should clean the pressure fittings and gun tip. Apply pressure to the fitting until grease comes out around the edges of the bearing. In bearings fitted with felt or other seals, you must be careful to avoid breaking the seals by over-pressure. If you use excessive pressure while you are lubricating the needle type of roller bearings, you may unseat the needles.