Why does excavator hydraulic oil turn black

Black hydraulic oil is very common, the newly bought hydraulic oil color is amber or light yellow, after a period of use will become brown or even black. Many digging friends believe that the black hydraulic oil is caused by too high temperature, but is it really the "trouble" caused by high temperature? Today, let's analyze it for you!

What are the causes of black hydraulic oil?

Internal impurity

Metal impurities such as iron filings are the main influencing factors. Among them, the most likely is the wear debris generated by the high-speed rotation of the pump, and all parts of the pump rotation are possible, such as bearing, volume chamber, etc. The hydraulic valve spool runs back and forth, and the grinding dust generated by the back and forth operation of the cylinder is generated, but this phenomenon will not occur in a short time.

If your excavator is newly bought, it will produce a lot of metal impurities in the run-in. When changing the oil, the hydraulic oil in the oil tank should be completely emptied, and the oil tank should be wiped clean with cotton cloth before adding new oil. If it is not emptied, there may be a large amount of iron filings remaining in the tank, which will also cause the new oil to be contaminated and blackened.

External environmental impact

① The pipeline seal of the excavator is not tight due to mechanical failure, aging oil seal and other reasons;

② The working environment of the excavator is too poor to block the filter element;

③ In the cleaning, oil change, maintenance process of dust prevention measures are not good, the operation of impurities into the hydraulic system.

Therefore, you need to check that your hydraulic system is closed and your breathing hole is intact; Check the exposed parts of the hydraulic part of the equipment to see if the seal is intact, such as the dust ring of the oil cylinder.

If your excavator often uses a crushing hammer, the reason for the black hydraulic oil is not only impurities, but also because the filling of butter is not standardized.

When filling butter, it is necessary to lift the crushing hammer and press the steel into the piston, and only need to fill half the gun of the standard butter gun for each filling. Because if the steel is not pressed when the butter is filled, the butter will be in the upper limit of the steel groove, and the butter will directly rise to the main oil seal of the breaking hammer when the steel is working, and the butter will be brought into the middle cylinder of the breaking hammer with the reciprocating movement of the piston, and then the hydraulic oil in the middle cylinder of the breaking hammer will be mixed into the hydraulic system of the excavator, so that the hydraulic oil is deteriorated and black.

Choose BONOVO for high-quality, customizable brush cutters for skid steers with fast delivery. Contact us today to discover how our superior products can enhance your land management tasks!

Excavator equipment manufacturers，Excavator fittings，Excavator accessories