Product Name: O-Ring (85 mm x 3 mm) – Part No. 05139720

Description:
This component is a metric O-ring seal with nominal dimensions of 85 mm inner diameter (ID) and 3 mm cross-section (CS). It is manufactured as a standard elastomeric sealing ring, typically made from nitrile rubber (NBR), Viton (FKM), or polyurethane, chosen for its compatibility with hydraulic fluids, water, and the pressure demands of waterjet systems .

The O-ring functions as a static seal between fixed mating surfaces within the hydraulic pump assembly of a waterjet intensifier system. Specifically, this part is listed as Item 3 in Table 12-7 of the Hydraulic Pump Assembly 20498668 . It is installed at the interface between the Piston Pump (05045505) and the Gear Pump (20498626), sealing the hydraulic fluid path to prevent oil leakage from the high-pressure hydraulic circuit .

Applications:

• Seals the interface between the piston pump and gear pump in the hydraulic pump assembly of a waterjet intensifier system

• Prevents hydraulic oil leakage at the stationary connection point between pump sections

• Used in the hydraulic pump assembly (20498668) that drives the intensifier pump

• Suitable for high-pressure hydraulic circuits in waterjet cutting systems

Features:

• Metric Dimensions: 85 mm inner diameter × 3 mm cross-section, conforming to standard metric O-ring sizing

• Static Sealing Application: Designed for use between non-moving, fixed mating surfaces within the pump assembly

• Hydraulic Fluid Compatibility: Material is selected for resistance to petroleum-based hydraulic oils

• Critical Sealing Component: Essential for maintaining hydraulic pressure integrity within the pump assembly

• OEM Specification: Listed in factory parts documentation for the Hydraulic Pump Assembly (20498668) 

Maintenance:

Failure Diagnosis:

• External Hydraulic Leakage: Visible oil weeping from the joint between the piston pump and gear pump indicates O-ring failure requiring immediate replacement

• Hydraulic Pressure Drop: Inability to maintain system pressure may indicate seal degradation or extrusion

• Visible Damage During Inspection: Inspect the O-ring for signs of nicks, cuts, flattening (compression set), hardening, or cracking during pump disassembly

• Fluid Contamination: Discovery of rubber particles in the hydraulic oil or filters suggests O-ring degradation

Inspection and Replacement Guidelines:

• Single-Use Component: The O-ring is a consumable sealing element. Always replace with a new one whenever the pump assembly is disassembled. Do not reuse old O-rings

• Clean Installation: Before installing a new O-ring, thoroughly clean the groove and mating surfaces with a soft, lint-free cloth. Remove all debris, old seal residue, mineral deposits, and corrosion

• Groove Inspection: Inspect the seal groove for nicks, burrs, sharp edges, or damage that could cut or abrade the new seal

• Lubrication: Apply a thin, uniform layer of manufacturer-recommended high-pressure grease or clean hydraulic oil to the O-ring during installation to prevent pinching, rolling, or tearing during assembly

• Proper Seating: Ensure the O-ring is correctly seated in its groove without twisting or warping before reassembling mating components

• Torque Compliance: When reinstalling the pump assembly, tighten all mounting hardware to the specific torque values listed in the equipment service manual to ensure proper O-ring compression without over-compression or damage

• Full Depressurization: Always fully depressurize the hydraulic system and follow lockout/tagout procedures before disassembling the pump assembly

• Storage: Store spare O-rings in a cool, dry environment (15–25°C, humidity <65%) away from direct sunlight, ozone sources, and chemicals to prevent premature aging

• Cross-Reference Compatibility: This O-ring is part of the Hydraulic Pump Assembly (20498668) and may be referenced under similar OEM numbers. Interchangeable with standard 85mm × 3mm metric O-ring specifications