DH55/60-7 Main Relief Valve
1. Product Overview
DH55/60-7 Main Relief Valve (commonly known as main gun) is a cartridge pilot-operated pressure control valve installed on the main control distribution valve of Doosan DH55, DH60-7 small crawler excavator.
It acts as the core safety component of the whole hydraulic system, limiting the maximum working pressure of the main hydraulic circuit. When system pressure exceeds preset value, the valve opens automatically to divert excess hydraulic oil back to the tank, protecting hydraulic main pump, main control valve, cylinders and pipelines from overload damage. High-quality interchange spare part can directly replace OEM component for equipment maintenance and overhaul.
DH55/60‑7 Main Relief Valve is a critical safety‑protection Hydraulic valve for excavator equipment. It limits maximum working pressure of the whole hydraulic system and prevents over‑pressure damage to components. This component is specially designed for Doosan DH55‑7 and DH60‑7 Machine, widely adopted for equipment maintenance and aftermarket replacement of construction machinery.
OEM Part Number: 410127-00304 / XKBF-00743 / XKBF-00173
Compatible Models: Doosan DH55, DH60-7, DX55, DX60; Hyundai R55-7, R60-7
2. Main Technical Parameters
Item Specification
Valve Type Cartridge Pilot Operated Main Relief Valve
Standard Factory Setting Pressure 20.6 MPa
Adjustable Pressure Range 18.0 ~ 23.0 MPa
Applicable Medium ISO VG46 anti-wear hydraulic oil
Operating Temperature -20℃ ~ +90℃
Sealing Material NBR; FKM high-temperature sealing optional
Body Material Alloy steel, quenching & tempering treatment
Installation Form Standard cartridge thread for DH55/DH60-7 main valve
Approximate Weight 0.14 kg
Mount Position Main control distribution valve
3. Working Principle
Under normal operation, the spring pushes the spool tightly against the valve seat, and the overflow passage remains closed.
Once hydraulic system pressure rises above preset pressure, hydraulic force overcomes spring tension to lift the spool. Surplus pressure oil flows back to hydraulic tank to restrict system peak pressure.
When pressure drops below set value, spring resets the spool and closes overflow channel, so hydraulic system maintains stable working pressure. It effectively suppresses pressure impact and prevents component overload failure inside hydraulic system.
4. Core Advantages
1. Specially matched for Doosan DH55 / DH60-7 excavator; installation thread, dimension and pressure characteristic fully consistent with original valve, direct plug-and-play replacement without modification.
2. Precisely ground spool and valve seat, excellent sealing property, low internal leakage, stable pressure holding during long-time urban construction operation.
3. High-strength alloy steel valve body, wear-resistant and impact-resistant, suitable for frequent load changes of small excavator working conditions.
4. Smooth pressure response, effectively reduce hydraulic shock and system heat generation, extend service life of the whole hydraulic components.
5. Pressure adjustable via tail adjusting nut; convenient on-site commissioning to match machine working requirements.
6. Cost-effective aftermarket replacement assembly, short delivery cycle for equipment maintenance.
5. Application Range
Main safety protection component for Doosan DH55, DH60-7 small excavator hydraulic system.
Widely used in municipal pipeline construction, landscaping, indoor demolition, small earthmoving and urban renovation projects.
6. Common Faults & Replacement Suggestion
Typical faults caused by defective main relief valve: Insufficient digging force, slow all actions, unstable movement, high hydraulic oil temperature, abnormal hydraulic noise.
