Leakage prevention in the pipe joint is in the hydraulic system, whether it is metal pipe joint or hose joint, there is a problem of leakage easily. The sleeve type pipe joint, mostly because of pipeline by external or large impact force, the card sets loose or tube deformation caused by the leak, you should check whether the card lost round, edge has no defect, the pipe end is intact and sleeve nut pressing degree, but also eliminate the pipeline external force. For flaredfitting, mostly because of excessive flaring, substandard quality or repeated disassembly, resulting in flaring deformation or cracks caused by leakage, the front again flared off. If the top pressure of the female cones is sealed, most of the leakage is due to the damage of the two cone surface, and the abrasive sand can be used to grind the conical surface. In some "C" ring on the end or outside sealing occasions, the leakage of the following reasons: "C" ring deformation caused by aging or leakage; the "C" ring assembly is not in place, the two plane connection or "C" uneven pressure ring is cut from causing leakage; "" ring without compaction, the elastic deformation caused by leakage; "a" ring spigot groove deep caused leakage. In this regard, the need to re select the same diameter and thick section "C" ring, can also be provided with a sealing plane rabbet groove of cutting or grinding, in order to reduce the rabbet groove depth, the "C" ring has enough elastic deformation (compression should be between 0.35-0.65mm). The pipe joint oil sheet, wool, steel board, combined sealing washer or sealant leak, whatever the material, should first check the seal is damaged, and rough conditions such as deformation, aging, and then take corresponding measures.