The reasons for the hydraulic oil of the excavator’s hydraulic system turning black after being equipped with break hammer are either that it contains metal impurities such as iron filings, or that the working environment is poor and external contaminants have entered the hydraulic oil.
Let’s take a look at the sources of iron filings and how to prevent them:
No. 1: The most likely source is the wear debris generated by the high-speed rotation of the pump. You need to consider all the components that rotate with the pump, such as bearings, chambers, etc.
No. 2: The wear debris produced by the back-and-forth movement of the valve core in the hydraulic valve and the movement of the cylinder. However, this phenomenon will not occur in a short period of time.
No. 3: Since it is a new machine, during the equipment’s break-in period, a large amount of iron filings will be produced. I wonder if you emptied the hydraulic oil in the oil tank completely when changing the oil, and then circulated the new oil through the system, wiped the entire oil tank clean with cotton cloth, and then added new oil. If not, there might be a lot of iron filings remaining in the oil tank, which could also cause the new oil to be contaminated and turn black.
Let’s look at the influence of the external environment: Check if your hydraulic system is sealed, and if the breathing holes are intact; inspect the exposed parts of the equipment’s hydraulic section to see if the seals are in good condition, such as the dust covers of the hydraulic cylinders, etc.
No.1 Was the hydraulic oil not completely replaced during the change?
No.2 Has the oil seal aged?
No.3 Could the poor working environment of the excavator have caused the filter element to get clogged?
No.4 Are there a lot of air bubbles in the hydraulic pump?
No.5 The hydraulic oil tank is in direct contact with the air. Over time, dust and impurities from the air will enter the oil tank, and the oil will definitely become dirty.
No. 6: The oil sample passed the particle size test and met the cleanliness requirements. This rules out the possibility of dust contamination. It can be confirmed that it is caused by the high temperature of the hydraulic oil! You can replace it with high-quality hydraulic oil, inspect the return oil filter and the cooling oil circuit. The key point is the hydraulic oil radiator! Regular maintenance in accordance with the regulations is necessary!
The reason for the darkening of the hydraulic oil in the breaker hammer: It is not only caused by dust, but also possibly due to improper addition of grease, as well as the failure of the dust-proof seal of the breaker hammer, which leads to the generation of black oil and cylinder seizure, and many other factors.
Post time: Jun-09-2025