Tips for diagnosing hydraulic cylinder failures

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This post was last edited by liyaojun001 on 2011-6-21 08:28. Based on the recommendations from Engineer Li in the hydraulic field, here are some tips for troubleshooting hydraulic cylinder problems: One of the main reasons why a hydraulic cylinder fails to function is that the pressure of the oil at the inlet is too low, in other words, the operating pressure is insufficient. The main reasons for insufficient operating pressure in a hydraulic system are faults in the hydraulic pump, drive motor, and pressure control valve. Other causes include a clogged oil filter, an excessively small diameter in the oil passages, and oil viscosity that is either too high or too low ； Excessive air enters the oil ； Severe pollution ； The pipeline is connected incorrectly ； Damaged pressure gauge, etc. When the hydraulic pump of an excavator is severely worn, it has a fatal impact on the excavator; therefore, such problems must be resolved promptly. Hydraulic expert Li shares with everyone that when repairing an excavator’s hydraulic pump, one should look for the causes of faults from the following three aspects: 1. Check for internal leakage in the boom cylinder. The simplest way to repair an excavator’s hydraulic pump is to raise the boom and see if it drops freely in a noticeable manner. If the drop is significant, disassemble the cylinder for inspection; if the seal ring is worn, it should be replaced. 2. Inspect the control valve of the hydraulic cylinder: First, clean the safety valve and check whether the valve core is worn; if it is worn, it should be replaced. If there is still no change after installing the safety valve, then check the wear condition of the control valve spool; the allowable gap is generally 0.06 MM, and it should be replaced if the wear is severe. 3. Measure the pressure of the hydraulic pump. If the pressure is low, make adjustments; if the pressure still cannot be increased, it indicates that the hydraulic pump is severely worn out.