Use only clean lubricant from clean, closed containers and keep it from becoming contaminated during regreasing operations. lubricate. grease. Do not over- The housing should be no more than about one-third full of Too much grease will cause churning, resulting in grease separa- tion, overheating, and grease leakage, Add grease sparingly observing precautions as to over-greasing. Complete regreasing is best left until the time of overhaul. More complete renewal of the grease can, when necessary, be accomplished by forcing out the old grease with the new. Thoroughly wipe clean those portions of the housing around the filler and drain plugs. Remove the drain plug and free the drain hole of any hardened grease which may have accumulated. With the machine running, add new grease through the filler hole until it starts to come out of the drain. Before replacing the drain plug, let the machine run for ten to twenty minutes to expel any excess grease. The filler and drain plugs should be thoroughly cleaned before they are replaced. CLEANING BALL BEARINGS At such times as the machine is disassembled for general overhauling, the housing may be cleaned of old oil or grease by washing with carbon tetrachloride. Open type bearings may be cleaned by placing them in wire basket suspended in a container of clean, cold petroleum solvent, or kerosene, and permitting them to soak for several hours. In stubborn cases, agitation in a hot oil bath may prove more expedient. Use a light transformer, spindle, automotive flushing, or motor oil not heavier than SAE-10 heated to about 220°F. In very bad cases, the bearings 3-32