The various actions of the front-end attachments of the excavator are achieved through the oil cylinder. The oil cylinder is easily affected by oil quality and external factors during frequent reciprocating movements, which may cause discoloration on the surface of individual precision piston rods.
Why is it colored?
Due to the complex composition of additives in hydraulic oil, under specific temperature and hydraulic oil pressure, the additives will crystallize and adhere to the surface of the precision piston rod. Under the shear force of the hydraulic cylinder oil seal, their discoloration phenomenon occurs. Different grades of hydraulic oil should not be mixed as much as possible, otherwise the quality of the oil will decrease, and in severe cases, the oil will deteriorate. Hydraulic oil contains various additives with specific effects. When mixed with different systems of additives, it can affect the performance of insulation materials and even cause additives to precipitate and deteriorate. In this case, it is also easy to cause piston rod coloring.

What should I do after changing color?
Discoloration is an occasional phenomenon, and hydraulic cylinders can be used with confidence. Due to the varying temperature and pressure conditions of the hydraulic oil in each cylinder, the fit clearance between the sealing components of the hydraulic cylinder and the precision piston rod varies even among the piston rods on the same hydraulic excavator. Therefore, some products may occasionally experience this phenomenon. This phenomenon will not affect its performance or shorten its service life.