Excavator operators with some work experience should have encountered the problem of discoloration of the excavator's hydraulic cylinder. At first, everyone may suspect that the discoloration is caused by poor cylinder quality. Here, the editor wants to tell you that in fact, the discoloration of the hydraulic cylinder is a common phenomenon. There are many reasons for the discoloration, and most of the time, the cause of the discoloration is not the quality problem of the cylinder itself.