GVO 4456617 Excavator Parts EX40UR-3 ZX35U-3 Auxiliary Relief Valve Pressure Relief Valve Hydraulic Control Valve

GVO 4456617 Excavator Parts EX40UR-3 ZX35U-3 Auxiliary Relief Valve Pressure Relief Valve Hydraulic Control 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-style main relief valve is a dedicated hydraulic pressure protection component for two classic Hitachi 3–4 ton class mini-excavators: the older EX40UR-3 model and its successor, the ZX35U-3 zero-tail-swing mini-excavator. Serving as the core pressure control valve within the main control valve assembly, it performs three critical functions: limiting the hydraulic system's maximum pressure, relieving pressure during instantaneous overloads, and maintaining stable pressure under load. It is an indispensable safety component for the hydraulic circuits of zero-tail-swing mini-excavators operating in confined spaces.

The valve spool features a precision-engineered sliding clearance (measured in microns), and all flow ports are chamfered and deburred to minimize erosion and cavitation damage to the valve body's inner walls caused by high-pressure fluid turbulence. The inlet incorporates a simple debris-blocking structure to prevent large particles—such as metal shavings or silt—from entering the spool sealing interface; this significantly reduces the risk of spool seizure or total pressure failure caused by poor hydraulic fluid cleanliness, making it well-suited for the maintenance habits of many mini-excavator owners who may delay filter replacements or neglect hydraulic fluid care.

All exposed metal surfaces of the valve body undergo quench-and-temper heat treatment followed by a black oxide anti-rust finish, while the threads receive additional passivation treatment. This ensures resistance to rust and oxidation during prolonged operation in muddy, waterlogged conditions or when parked outdoors exposed to the elements, preventing difficult issues like thread seizure or the inability to unscrew the valve during future repairs. The standard cylindrical cartridge design allows for extremely simple installation and removal; maintenance personnel can replace the valve directly from the outside of the valve block without dismantling the entire main control valve assembly. This drastically reduces repair time and minimizes the risk of oil leaks associated with reassembling the valve block—perfectly aligning with the operational needs of rental equipment fleets that face tight schedules and require rapid repair and turnaround.

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.