31Y1-12630 Boom Adjust Cylinder Seal Kit — Product Overview

The 31Y1-12630 Boom Adjust Cylinder Seal Kit is a heavy-duty aftermarket replacement for Hyundai excavators. Designed for the boom adjust cylinder with 100mm rod and 160mm bore dimensions, this kit is manufactured to Hyundai OEM specifications using premium sealing materials etc.

The boom adjust cylinder is a specialized hydraulic component on mid-to-large Hyundai excavators. It controls the angular positioning of the boom relative to the upper structure — enabling the operator to fine-tune the boom’s working angle for optimal digging geometry. With a 160mm bore, this is one of the larger cylinders in the Hyundai excavator platform, handling substantial structural loads during angular adjustment. Seal failure causes angle drift, reduced digging precision, and hydraulic oil leakage at the cylinder gland.

The 31Y1-12630 kit uses high-grade polyurethane rod seals, PTFE backup rings for extrusion protection under maximum adjustment pressure, and NBR static seals etc. DJF Seals supplies this kit at factory-direct wholesale pricing.

Technical Specifications

Compatible Models

• Hyundai R210LC-7 — Boom Adjust Cylinder
• Additional Hyundai mid-to-large excavator models with boom adjust cylinder

Key Features & Benefits

• Heavy-Duty 160mm Bore — One of the largest cylinder bores in the Hyundai platform. Built for the substantial structural loads of boom angular adjustment on mid-to-large excavators.
• Angular Precision — 100mm rod seal engineered to maintain precise boom angle positioning under continuous vibration and side loads during excavation.
• Complete Reseal Kit — Rod seal, piston seal, wiper, O-rings, and backup rings included for a full boom adjust cylinder rebuild.
• Extrusion-Protected — PTFE backup rings prevent seal extrusion under the high adjustment pressures of the 160mm bore cylinder.
• Factory-Direct Wholesale — Competitive pricing with flexible MOQ. Sample orders accepted for quality verification.