Kato HD400-2 Pilot Valve Seal Kit Control Levers

This pilot valve seal kit is engineered for the hydraulic control lever assembly on Kato HD400-2 crawler excavators. It contains precision-molded nitrile rubber (NBR) O-rings, backup rings, and dust seals designed to withstand pilot circuit pressures up to 3.5 MPa and main system pressures of 35 MPa. The kit restores sealing integrity between the pilot valve spool and body, eliminating internal leakage that causes drift or slow response in boom, arm, and swing functions. All components meet OEM dimensional tolerances for direct installation without modification. Compatible with Mitsubishi 6D31T powered variants across the HD400 series including HD400-5 and HD400-7 models. Material composition utilizes high-grade NBR compound resistant to petroleum-based hydraulic fluids, operating temperatures from -20°C to 120°C. The kit includes all necessary seals for a complete pilot valve rebuild: spool seals, port seals, and end cap seals. Cross-references aftermarket SKU ES37841 and MotoViking branded assemblies. Recommended replacement during scheduled hydraulic maintenance or when control lever drift is diagnosed.