Grease

Assignment

Grease should be water-repellent and anti-oxidant, allowing little friction when cold. It should withstand high pressures and aggressive chemicals, prevent corrosion and maintain all these attributes for a long time. Some of these demands exclude each other, e.g., the low frictional properties and the longevity.

Function

Grease is formed, when lyes, like potash lye or calcium hydroxide, react with fatty acids, creating soaps. Mixing it with mineral oil, heating it up and cooling it down in a certain manner, creates grease. Basically, what we are left with, is thickened lubrication oil. An important measure of it's consistency, is it's ability to penetrate. Grease is widely used, for roller bearings (e.g., wheel bearings) and even for the lubrication of rails. If it is not possible to use oil for sliding bearings, grease is an alternative. If the grease is to be used under special conditions like high temperatures, solid lubricants like graphite or molybdenum sulphide may be added.

Important

More important than the quality of the grease and the amounts stated in the manufacturers instructions, the mechanic should pay special attention to the proper sealing. The sealing protects the grease filling against outside influences and of course, vice versa. This is why regular checking of the bellows (gaiters), e.g., in the steering system, the drive shaft and other oil-lubricated assemblies, still remains necessary for the future. 02/12