GVO 4708396 Auxiliary Relief Valve Pressure Relief Valve Hydraulic Control Valve

Product Specification

GVO 4708396 Auxiliary Relief Valve Pressure Relief Valve Hydraulic Control Valve Safety Valve EX55 Excavator Parts

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-type main relief valve is a dedicated main control pressure protection valve for the hydraulic system of the Hitachi EX55 mini excavator. It is a core pressure control component of the multi-way distribution valve in the Hitachi EX55 mini excavator, directly determining the maximum working pressure threshold of the entire hydraulic system. It undertakes three core functions: overload relief, load pressure stabilization and maintenance, and constant system pressure regulation, making it a crucial safety valve for the mini excavator's hydraulic circuit.

The Hitachi EX55, a classic 5.5-ton mini excavator, is widely used in indoor demolition, landscaping, municipal pipeline renovation, and construction in confined spaces. Its hydraulic system experiences frequent start-stop cycles and large load fluctuations. The stability of the relief valve directly affects digging force, lifting power, and the smoothness of rotation. Simultaneously, it provides ultimate overload protection for the main hydraulic pump, cylinders, travel motor, swing motor, and high-pressure oil pipes, preventing damage such as oil seal rupture, pipe bursts, pump tank scoring, and valve block internal bore erosion caused by pressure buildup during digging and impacts from the breaker hammer.

This product is precision-machined to a 1:1 scale with the original Hitachi EX55 relief valve. The external thread mounting specifications, cartridge valve body diameter, oil hole position, sealing groove, and adjusting end structure are completely identical to the original part. It is a direct cartridge replacement part, requiring no valve hole grinding or gasket installation. Assembly is complete simply by inserting it into the main control valve chamber and tightening. It perfectly matches the oil circuit logic of the original EX55 hydraulic valve block, fundamentally solving common maintenance  points such as inaccurate pressure calibration, excessively loose or tight thread fit, severe internal leakage, insufficient pressure, weak operation, and stalling/speed drop in inferior aftermarket valves.

The valve body is integrally CNC machined from 40Cr alloy steel bar. The mating surfaces of the valve core and valve seat undergo high-precision grinding and high-frequency quenching hardening treatment, resulting in high surface hardness, resistance to high-pressure oil erosion, and resistance to wear from hydraulic oil impurities. The external thread is precision rolled, and the sealing ring provides strong sealing reliability, making it less prone to leakage under long-term high and low pressure alternating conditions. By eliminating problems such as valve core jamming, internal leakage due to sealing surface wear, and pressure drift from the material and precision machining aspects, it provides stable and reliable hydraulic pressure for the Hitachi EX55 mini excavator.

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.