1. When the SKF angle contact ball  bearing  http://www.alierbearings.com/brand/skf/index13.html  runs to a certain period (or maintenance period), all the bearings are removed;
2. Soak and clean the bearings with clean diesel oil or kerosene. If technical conditions are better, open the seal cover to clean.
3. Clean and clean the oil after cleaning, and the appearance inspection shall be damaged;
4. A wooden rod (preferably hollow tube) with a diameter of about 150mm and diameter of angular contact ball bearing with an equal diameter, fixed one bearing at one end;
5. While using the hand to quickly rotate the bearing, the other end of the wood rod (wooden tube) will be heard on the ear or the microphone of the audio amplifier to listen to the bearing turning noise;
6. After fixed bearing, the rod is moved laterally to check whether the bearing is wearing loose;
7. SKF bearings with severe loose, excessive rotational noise and serious defects shall be eliminated and replaced in the same model;
8. Take a bucket of grease (high quality yellow dry oil) to melt (not overheat), and dip the tested bearing into the bucket and soak it in no bubble overflow.
Remove the bearing before the grease cools, and the residual grease is small.
After the grease cooling, remove the Angle contact ball bearing, and the residual grease is much.
Determine the amount of grease residues as needed.
9. Use a soft cloth or toilet paper to clean the grease outside the bearing to install the SKF bearing into the pulley, and the maintenance work will be finished.