708-2L-56302 423-46-43200 Pressure Relief Valve Pressure Compensation Valve

Product Specification

708-2L-56302 423-46-43200 Pressure Relief Valve Pressure Compensation Valve PC200-6 PC200-7 PC200-8 PC240-7 PC360-7 Excavator

Product Description

The GVO excavator relief valve, compatible with Hitachi excavators, is a key pressure control valve in the hydraulic system. It regulates hydraulic pressure, releases overload pressure, protects core hydraulic components such as the main valve and hydraulic pump, and ensures stable operation of the entire machine.

This relief valve is precision-machined from high-quality steel and undergoes overall quenching treatment. Equipped with oil-resistant and high-pressure-resistant seals, it boasts excellent sealing performance, impact resistance, and wear resistance. Suitable for the high-pressure hydraulic conditions of excavators, it effectively prevents internal leakage, pressure loss, operational instability, and vibration.

Product Introduction

This GVO cartridge-style main relief valve is a critical pressure-protection component within the hydraulic control systems of Komatsu’s classic, flagship PC200-6, PC200-7, PC200-8, PC240-7, and PC360-7 excavators. Integrated into the main control valve body, it performs three core functions: limiting maximum system pressure, relieving pressure during heavy-load overloads, and maintaining constant load pressure. It directly determines the machine's digging force and the coordination of simultaneous movements, while providing ultimate overload protection for expensive hydraulic components such as the main pump, cylinder assemblies, travel motors, and high-pressure hoses.

The upper sliding section of the valve body is fitted with a high-temperature-resistant fluororubber composite seal, designed to withstand extreme summer engine-compartment oil temperatures and hydraulic fluid corrosion, as well as to resist hardening, cracking, and permanent deformation caused by rapid temperature fluctuations. The middle section features two independent stepped grooves equipped with thickened, oil-resistant nitrile rubber O-rings; this multi-layer sealing configuration creates a dual-protection barrier that completely prevents high-pressure hydraulic fluid from leaking at the interface between the valve body and the valve block. Even during continuous operation in harsh environments—such as muddy rainy-season sites, quarries filled with airborne dust, or conditions with neglected oil maintenance—the valve remains free from external fluid bypass or leakage through threaded gaps.

The external mounting threads are produced using a precision roll-forming process, resulting in a smooth, well-defined thread profile that ensures seamless engagement during installation without stripping or damaging the internal threads of the control valve, thereby avoiding secondary repair costs. The large hexagonal locking nut at the base distributes stress evenly; the valve body remains securely fastened and immovable despite the shocks of heavy-duty digging, the jolts of long-distance off-road transport, and high-frequency swing vibrations, effectively preventing system pressure drift or instability caused by vibration. The valve body undergoes a blackening and passivation anti-rust treatment, offering exceptional resistance to moisture-induced rust and the electrochemical corrosion caused by mud and water at construction sites. It resists rusting and valve-spool seizing—even during prolonged outdoor storage or operations in damp underground environments—thereby significantly reducing the labor hours required for repeated disassembly and pressure adjustment, as well as minimizing downtime losses. It is ideally suited for the high-intensity operational demands of rental fleets, which involve frequent equipment turnover and continuous 24-hour shift work.

Packaging & Shipping

We use high-strength, environmentally friendly paper export packaging, which is reinforced, cushioned, and moisture-proof, suitable for long-distance international logistics transportation, and meets cross-border freight and environmental protection standards. International transportation adopts formal cross-border logistics, with full tracking of logistics information and supporting customs clearance documents to ensure smooth customs clearance and timely delivery of goods overseas.

Company Introduction

The GVO brand is a manufacturer of hydraulic components. We mainly produce the most comprehensive range of pilot pumps, gear pumps, relief valves, hydraulic pumps, electrical components, hydraulic parts, engine assemblies, traveling assemblies, rotating assemblies, distribution valves, and other components.

We are factory direct sellers without any middlemen profiting from price differences. The quality is definitely the best for you because we are the ones who produce them. We cannot tarnish our reputation. The prices are also the most favorable for you. There is a stable delivery speed.

We value every customer and provide you with the best service. We offer pre-sale, in-sale, and after-sale guarantees. Any problems will definitely be resolved for you. We are always available to serve you.