Several misunderstandings about the use of grease

Lubricating grease is an important type of lubricant used in automobiles. It is a thickened lubricating oil with a viscous semi-solid appearance, similar to butter, commonly known as butter or yellow dry oil. There are many incorrect understandings and practices when using lubricating grease in cars, which have caused some unnecessary losses. The following are the details.Adding grease to the universal joint cross shaftIn general car maintenance manuals, it is explicitly stipulated that the key teeth and intermediate bearings of the expansion sleeve of the transmission shaft use calcium grease, and the needle roller bearings of the cross shaft and the intermediate bearings of the rear axle transmission shaft of three axle drive vehicles use gear oil.Lubricating grease is an important type of lubricant used in automobiles. It is a thickened lubricating oil with a viscous semi-solid appearance, similar to butter, commonly known as butter or yellow dry oil. There are many incorrect understandings and practices when using lubricating grease in cars, which have caused some unnecessary losses. The following are the details.Adding grease to the universal joint cross shaftIn general car maintenance manuals, it is explicitly stipulated that the key teeth and intermediate bearings of the expansion sleeve of the transmission shaft use calcium grease, and the needle roller bearings of the cross shaft and the intermediate bearings of the rear axle transmission shaft of three axle drive vehicles use gear oil.

However, in practical work, due to the lack of refueling equipment, some repairmen mistakenly use calcium based grease to lubricate the cross shaft needle roller bearings for the sake of convenience, resulting in a large number of cross bearings being damaged too early. Due to the fact that the nozzle for adding gear oil to the universal joint cross shaft is a very ordinary grease nozzle, it often leads to a misunderstanding that butter cannot be added to the needle roller bearing. Due to the high viscosity of butter, when a butter gun is used to add butter to the inner chamber of the cross shaft through the oil nozzle, there is a high resistance for butter to enter the narrow oil groove oil passage. At this time, butter will overflow by pressing against the pressure reducing valve opposite the oil nozzle, which makes the repairman mistakenly believe that the bearing has been filled with oil. In fact, butter not only cannot enter between the needle rollers, but also reaches the end face of the cross shaft neck, which is also difficult.

Therefore, the practice of using butter instead of gear oil to lubricate the universal joint cross shaft should be changed, and gear oil should be added using a gear oil pressure gun. The more lubricating grease is added to the wheel hub bearings, the better. Some drivers fill the wheel hub bearings and cavities with lubricating grease when maintaining the wheel hub bearings, thinking that the more is better, but in fact, it is not. Filling the wheel hub cavity with lubricating grease will cause most of the lubricating grease to be thrown into the wheel hub cavity, which not only cannot be filled into the bearings, but will flow to the brake shoes in the dynamic drum, causing brake failure. At the same time, due to increased rolling resistance, the wheel hub will overheat and cause unnecessary waste. The correct approach is to apply a thin layer of lubricating grease in the wheel hub cavity. This not only ensures lubrication of the key parts, but also facilitates heat dissipation and cooling of the wheel hub, and can save a lot of lubricating grease.

Adding lubricating oil to make the lubricating grease thinner. Some repairmen like to add lubricating oil to the original lubricating grease for dilution when using lubricating grease in winter, which is incorrect. Because lubricating grease is a colloidal structural system composed of a thickener and base oil, the thickener forms a structural network that adsorbs the base oil (usually ordinary lubricating oil) into the network, forming a stable structural system that prevents the separation of the thickener and base oil. If lubricating oil is added after greasing, although it is stirred, it cannot be evenly dispersed and contained in the network, making it easy to separate and lose during use, which is not conducive to lubrication. If lubricating grease with low viscosity is needed in winter, calcium based lubricating grease with small number 1 or 2 can be selected.