The front-end working device of the wheel loader is mainly a bucket. The normal operation of the bucket requires the cooperation of the bucket cylinder, arm cylinder and boom cylinder to complete various compound actions. One of the more common problems with these cylinders is pressure relief, which may manifest itself in boom lowering, arm lowering, and bucket automatic release.
General troubleshooting methods:
1. The safety valve with and without rod cavity of the oil cylinder can be switched first. After switching, you can observe whether the fault phenomenon disappears. If the arm failure disappears at this time, it means that the internal leakage valve of the rodless cavity of the cylinder is seriously leaking and needs to be repaired or replaced.
2. The reversing safety valve will still show the phenomenon of arm dropping. Check the hydraulic oil return filter element to see if there are rubber chips or iron filings on the filter element. If there are rubber fragments on the oil return filter element, it is likely that the oil seal is badly worn. The oil seal of the cylinder needs to be replaced afterwards.
3. If the arm failure is still the same, check the hydraulic circuit fixed valve. When disassembling, check whether the wear is serious, and the holding valve should be polished, repaired or replaced in time.
If, after checking and replacing the holding valve, the loader still has the arm drop phenomenon, the main control valve should be disassembled, all the valve cores on the hydraulic circuit should be checked, and repaired or replaced in time.
Dropping the loader stick is a common failure. The stick drop of most loaders is caused by leakage inside the cylinder due to oil seal wear. During the inspection process, simple points of failure can be checked first. The wear of each spool in the main control valve will not occur until the loader is used for a long time, and the maintenance of the main control valve is a complicated process. It is recommended to check.
