4451786 Original Excavator Connector Information Valve for Hitachi ZX110 ZX200 ZX240-3 ZX450 ZX600 Z

Part number 4451786 is usually listed as REDUCER in Hitachi's original part number system; S (reducing joint/transition joint/connecting sleeve type) belongs to the "pipe fittings and valve block accessories" branch of the hydraulic system, rather than the movable electro-hydraulic valve body. It is not cross model universal: the same part number may only correspond to a certain generation of pump/valve block/cylinder pipe (such as pump outlet flange to hose, valve block test port to joint, or fixed liner), so the formal procurement caliber should be - the Hitachi EPC lock 4451786 is located in the drawing number, and the complete machine model+serial number+hydraulic pump/valve block/cylinder nameplate photo or old part outer label should be provided at the same time; Otherwise, if it looks like a joint, it is also prone to inconsistent threads/steps/sealing surfaces.

Its job is to "reliably connect" two oil ports with different nominal sizes or sealing forms, and provide the correct sealing interface: the common form is a steel stepped pipe joint body/liner, with PT (G) thread, UNFPA/SAE thread or flange sealing surface, and the key processing surface is deburred, edge protection and rust prevention (phosphating/galvanizing). The sealing method is often metal (74 ° cone/plane+O-ring groove) to ensure long-term non leakage under system pressure up to 35MPa, continuous vibration and oil immersed environment. The so-called "information valve related" is usually only because it is installed on the outside of the valve block (test port/drain port/pressure reducing interface) to play the role of "adapter/positioning/blocking support" - its own properties are still the accuracy and sealing geometry of the pressure bearing fittings, rather than the valve core action.

Daily visual inspection only: whether there is continuous oil leakage and gray lines on the outer surface; Once there is oil leakage, do not just "tighten half a circle" - first confirm if there are scratches on the sealing surface, residual old O-rings, or misaligned threads. When disassembling: ① Release pressure and clean the surrounding mud and sand first; ② Never use pliers to directly bite the sealing surface/edge (it is easy to bite out the leakage groove); ③ Before installation, clean the threads, sealing surfaces, and old rubber/O-rings thoroughly, and determine whether to dry install or use designated sealant according to the position; ④ Use the correct size wrench to apply force to the hexagonal block/flange, and tighten it according to the specified torque of the valve block/pump port (over tightening will cause the soft material valve block orifice to expand and deform, resulting in leakage). If cracks, thread slippage, or damage to the sealing step are found on the body, replace it directly with the original factory 4451786; It is not recommended to continue using 'car modification'.