GVO 0828301 4608478 Excavator EX60-5 EX70-5 ZAX70 ZAX80 Main Relief Valve Pressure Relief Valve Safety Valve

GVO 0828301 4608478 Excavator EX60-5 EX70-5 ZAX70 ZAX80 Main Relief Valve Pressure Relief Valve Safety Valve

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 core component for pressure protection in Hitachi's classic 4-8 ton mini excavators, precisely designed for their distribution valves. It accurately covers older EX series models like the EX60-5 and EX70-5, as well as newer ZX series mini excavators like the ZX70 and ZX80. It is a 1:1 replica of the original factory valve bore diameter, thread pitch, insertion depth, valve core stroke, and internal pressure regulating structure. The valve bore is universal across all four models, allowing for direct interchangeable installation. It is an indispensable overload safety pressure relief barrier for the hydraulic circuits of Hitachi mini excavators.

The valve body is made of high-toughness alloy structural steel, forged into a single piece. This completely eliminates the inherent defects of cheap aftermarket cast iron valve bodies, such as easy cracking under high pressure, slight deformation under long-term reciprocating loads, and easy erosion and scoring of the sealing surface by high-speed, high-pressure oil.

The valve core, valve sleeve, and valve body—all core pressure-bearing components—undergo three rigorous precision machining processes: full-size integrated precision cutting on a CNC lathe, high-precision centerless grinding of the outer diameter, and diamond ultra-precision honing of the valve sleeve inner bore. The clearance between the valve core and valve sleeve is controlled within micron-level ultra-precision tolerances, minimizing internal oil leakage under high-pressure conditions. This fundamentally solves common industry problems such as pressure regulation drift, insecure locking, and weak or ineffective instantaneous pressure relief under heavy loads.

All components subjected to pressure shock undergo a dual strengthening process of tempering heat treatment and surface carburizing and quenching. This results in uniform hardness distribution throughout the valve body, significantly improving resistance to high-frequency hydraulic shock and fatigue creep. It can stably withstand tens of thousands of reciprocating opening and closing pressure shocks up to 32MPa without experiencing valve core jamming, external thread stripping or disengagement under stress, or permanent deformation of the sealing ring mounting groove due to compression.

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.