John Deere O-Ring - R518543

Key Features

• Engineered to maintain sealed pressure boundaries and prevent hydraulic fluid escape across static joint interfaces
• Synthetic nitrile rubber compound provides sustained elasticity when exposed to petroleum distillates, water-glycol coolants, and abrasive particulate suspensions
• Uniform cross-sectional geometry delivers consistent compression set resistance, eliminating channeling or blowout under pulsating pump cycles
• Manufactured to reproduce original equipment dimensional tolerances, allowing direct replacement without gland re-machining or fastener retorque

Product Details

• Manufacturer Part Designation: R518543
• Component Type: Hydraulic O-Ring / Static Elastomeric Seal
• Materiel Base: Buna-N (Nitrile) with integrated thermal aging inhibitors
• Shore A Hardness: 70 ±5
• Optimal Service Environment: -40°F to +250°F (-40°C to +121°C)
• Geometry Class: Circular cross-section rated for ISO 6149-1 and SAEJ1453 compliant sealing grooves

This seal is sized and compounded to restore factory leak rates in hydraulic pump outlets, valve bank gasket seats, and cylinder rod ports where repeated thermal cycling would degrade standard rubber grommets.

Compatibility

• John Deere tractor and combine platforms utilizing enclosed hydraulic reservoirs and gear-driven pumps
• Hearson hydrostatic transmissions, integral flow-control spools, and auxiliary coupler manifolds
• Agricultural implement control cylinders, loader bucket pivot bearings, and steering axis glands
• Matches OEM reference listings for JD seal kit part numbers 8200-4624, 66-7727, and replacement designations FRU 518543