🔧 420-00257 MAIN CONTROL RELIEF VALVE

✅ What it is

Part number: 420-00257
Component name: Main Control Relief Valve (Main Relief Valve)

This is a primary pressure safety valve used inside the main control valve block of hydraulic systems—especially in excavators.

🏗️ Where it is used

This exact part number is widely used in construction machinery, especially:

• Doosan excavators (DX225, DX300, Solar series, etc.)
• Also cross-referenced in:
  • Hitachi EX200 / ZX200
  • DH220 / DH370
  • JCB JS series

👉 That means it’s a cross-compatible OEM-type hydraulic valve used across multiple brands.