For some second-hand construction machinery and equipment that have been idle for a relatively long time, old construction machinery and equipment. Before use, necessary tests must be conducted on the equipment.

Engine phenomena: Abnormal exhaust, operation and sound of the engine, difficult to start and slow acceleration. The oil in the hydraulic system is contaminated. The external and internal oil leakage of hydraulic components, pipelines and joints is severe. The hydraulic cylinder cannot be locked and automatically retracts. The transmission chains of all the control handles of the entire machine are loose, causing obstruction and difficulty during operation.

The main reasons are prolonged overwork and operation in an environment that does not meet the requirements. Daily maintenance is not timely, and major, medium and minor repairs fail to meet the standard requirements.

Measures

(1) Strictly manage and continuously improve the technical quality of operators to ensure the correct use of construction machinery.

(2) Strengthen the daily maintenance and inspection of equipment to improve its integrity rate.

(3) Enhance the technical proficiency and sense of responsibility of maintenance personnel to ensure the quality of major, medium and minor repairs.

Appropriately increase dedicated maintenance equipment, tools, instruments and technical data. Adjustment and repair of machinery. Adjustment and repair methods:

(1) Repair of gear pumps: Gear pump wear mainly involves the wear of the inner surface of the pump casing, the tooth top and the tooth thickness. The repair method is: apply a layer of metal coating liquid to the worn area on the inner surface of the pump casing to restore its original size. For gears, electroplating can be applied to the tooth top and tooth thickness areas to restore the dimensions of the tooth thickness and tooth top. Bushings are generally replaced but not repaired. When replacing a new bushing, it is necessary to pay attention to its axial length and leave no space. Several used gear pumps of the same model can be measured, and then the gears and pump bodies with relatively less wear can be selected for recombination and assembly, and tests can be conducted on the test bench.

(2) Repair of Hydraulic Cylinders: The causes of internal and external leakage in hydraulic cylinders: Firstly, the surface of the piston rod (or plunger) is severely worn or has grooves pulled out. It can be repaired by electroplating or metal brush plating methods. The second issue is the wear on the inner surface of the guide sleeve. As the guide sleeve is inexpensive, it is usually replaced. The third issue is that the hydraulic cylinder body itself is severely worn or has deep grooves pulled out, or there are cavitation areas on the inner wall of the cylinder body. This can also be repaired by brush plating process. The fourth point is that the sealing gasket on the piston is worn out. At this time, it can be replaced.

Internal leakage and external leakage can both cause the hydraulic cylinder to automatically retract. There are three inspection methods for the hydraulic cylinder installed on the vehicle: The first is to use a dial indicator. Attach the magnetic indicator base to the piston rod of the hydraulic cylinder, and press the pointer against the end face of the cylinder barrel. Observe the change value of the pointer before and after the engine is turned off for 15 minutes (including the following two methods), which is the retraction amount of the hydraulic cylinder. The second method is to stick a piece of paper on the extended piston rod with grease and measure the change in the distance from the upper end of the paper to the end of the hydraulic cylinder, which is also the retraction of the hydraulic cylinder. The third method is to lock a rubber plate that can be released and locked onto the piston rod, and the measurement method is the same as that of using a paper sheet. The above-mentioned detection method is also a way to determine whether the hydraulic cylinder is leaking internally and to what extent. Based on the measured retraction of the hydraulic cylinder, the wear degree of the seal on the piston and the service life of the equipment can be accurately calculated. If the service life is very short, it can be determined that the seal was damaged due to improper assembly methods. This is very useful for correcting incorrect assembly methods and judging the degree of internal leakage in hydraulic cylinders.

        Tianhang Forklift Machinery Co., Ltd. acts as an agent for Hangzhou forklifts, offering a full range of Hangzhou forklifts, model selection for warehousing equipment, whole machine trade-in, various brand forklift parts, forklift after-sales maintenance services, and second-hand forklift selection, among other integrated services.