How to maintain four point angular contact ball bearings?

Four point angular contact ball bearings maintenance method:
1. When the four point angular contact ball bearings are operated for a certain period of time (or maintenance period), the four point angular contact ball bearings are all removed;
2. Immerse the four point angular contact ball bearings with diesel or kerosene for cleaning. If there are technical conditions, it is best to open the sealing cap to clean;
3. After cleaning, dry the cleaning oil and check the appearance of the four point angular contact ball bearings for damage;

4. Use a wooden rod with a diameter of about 150 mm and a diameter of four point angular contact ball bearings (preferably a hollow tube), one end of which is fixed with a four point angular contact ball bearings;
5. While rotating the four point angular contact ball bearings by hand, put the other end of the wooden rod (wood tube) on the ear or the audio amplifier microphone to hear the bearing rotation noise;
6. Fix the four point angular contact ball bearings and then move the stick horizontally to check whether the bearing is loose or not.

7. Four point angular contact ball bearings with severe looseness, excessive rotating noise and serious defects should be eliminated and replaced by the same model;
8. Take a bucket and melt the appropriate amount of grease (high-quality yellow dry oil) with a simmer (not overheated). Place the four point angular contact ball bearings in the bucket and soak them in a bubble-free overflow. Remove the four point angular contact ball bearings before cooling the grease. The amount of residual grease is small. After the grease is cooled, remove the four point angular contact ball bearings and the amount of residual grease is large. Determine the amount of grease remaining as needed.
9. Wipe the outer grease of the four point angular contact ball bearings with a soft cloth or toilet paper to assemble the four point angular contact ball bearings onto the pulley. The maintenance work is over.