Your current location:Home - News - Industry News Back
Dig oil cylinder discoloration (oil cylinder black) fault
Class:Industry News Pubdate:2019-09-09 11:39:56 Browse:0 [Back]

Cylinder discoloration is a common phenomenon, there are many reasons, and most of the reasons for discoloration have nothing to do with the quality of the cylinder. The following is a look at the causes of oil cylinder discoloration and solutions.

Failure phenomenon:

Excavator oil cylinder discoloration (oil cylinder black), hydraulic oil for the company, only more than 500 hours, do not know how to return a responsibility?

Analysis of oil cylinder discoloration (oil cylinder becomes black) fault:

Usually there is a process of oil cylinder discoloration, the first oil cylinder will appear blue phenomenon, and then the color will gradually become dark and purple, until it becomes black.

In fact, the oil cylinder discoloration is not the chemical reaction itself, but the surface is covered with a layer of color film, so it seems that the oil cylinder discoloration. Let's first analyze the causes of oil cylinder discoloration.

1. Big temperature difference between inside and outside the oil cylinder

This often happens in winter. When the excavator works for a long time, the temperature of the hydraulic system rises while the ambient temperature is very low. At this time, there is a big temperature difference between the inside and the outside of the cylinder. In this case, the cylinder rod can easily cause the discoloration of the cylinder.

Poor quality of hydraulic oil

When excavators replace hydraulic oil, many bosses, in order to save money, buy not the original hydraulic oil, so it is easy to cause oil cylinder discoloration. Because the hydraulic oil will add a kind of extreme pressure anti-wear additives, different manufacturers brand of hydraulic oil in the ratio of additives is not the same, so mixed will occur discoloration, and even affect the hydraulic system.

Three, cylinder rod surface impurities

When the excavator is working, the cylinder rod of the hydraulic cylinder is often in contact with the external environment, which is easy to attach dust and impurities, especially in bad working conditions, which will be more serious. If not cleaned in time, with the accumulation of dust impurities will also make the cylinder discoloration.

If the blue color is found, it may be caused by the additives in the oil seal and hydraulic oil attached to the cylinder stem at high temperature. If it is turned black, it may be the reason why the lead contained in the spray inside the wear resistant sleeve is attached to the cylinder stem.

There are fine lines on the surface of cylinder rod

Another possibility is the quality of the cylinder rod. Cylinder rod surface is very difficult to find our naked eye cracks fine lines, the main reason is that the piston rod in the process of electroplating, surface heating control is not uniform, there will be cracks fine lines. It takes a magnifying glass to see this.

The above mentioned reasons for discoloration, the following will talk about the excavation of oil cylinder discoloration (oil cylinder black) solution.

One, if the surface of the oil cylinder appears small and small area of blue, you can not do processing, usually this situation in the work for a period of time, the blue will automatically disappear.

Two, if found discoloration is very serious, then it is necessary to replace the new oil seal and wear sleeve, at the same time check the hydraulic system, to avoid the appearance of high temperature hydraulic oil. This usually goes away after a while.

Three, if the front part of the bucket cylinder discoloration, which indicates that the temperature of the hydraulic oil is too high, we need to clean the radiator, reduce the temperature of the hydraulic oil when working.

Four, if it is the replacement of other brands of hydraulic oil after the cylinder discoloration, should immediately replace the original factory of hydraulic oil, do not penny for pound, so as to avoid damage to the hydraulic system and cylinder.

5. If the oil cylinder cracks and causes discoloration, this is the problem of the oil cylinder. If possible, coordinate with the manufacturer and agent to solve the problem, or purchase and replace the oil cylinder by yourself.


There are a variety of reasons for oil cylinder discoloration, some are caused by the external environment, and most of the main reason or their own problems. For example, the quality of hydraulic oil, hydraulic oil high temperature, cylinder quality and so on, in fact, these are we need to pay attention to some problems in the daily maintenance process.

Cylinder discoloration is just a small warning of hydraulic system failure, once found can not be paralyzed, you need to carefully check the hydraulic system, compared with the above several aspects of the inspection is where the problem.

Quanzhou tianlei construction machinery co. LTD