Description
55204 Hydro-Gear O-Ring 137 Square Profile 2.05″ x 0.099″ (OEM-Spec)
The Hydro-Gear 55204 O-Ring (137, 2.05″ x 0.099″) is a genuine OEM-spec sealing component engineered for use in Hydro-Gear hydrostatic transmissions, pump assemblies, and other high-pressure hydraulic systems. Designed to precise dimensional tolerances, this square-profile O-ring provides robust sealing performance between mating surfaces to prevent fluid leakage, maintain hydraulic pressure, and protect internal components from contamination. Built to Hydro-Gears exact specifications, the 55204 O-ring ensures long service life and dependable operation in demanding turf and drive applications.
Product Details
Manufacturer Part Number: 55204
Brand: Hydro-Gear (OEM-Spec)
Part Type: O-Ring Seal (137, Square Profile)
Dimensions: 2.05 ID 0.099 Cross-Section
Profile: Square (rectangular sealing profile)
Function: Hydraulic and fluid-system sealing
Material: Durable elastomeric compound (application-specific)
Application: Hydro-Gear hydrostatic transmissions and pump systems
OEM Status: Genuine Hydro-Gear replacement part
Function
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Provides a reliable fluid seal between mating surfaces in hydrostatic systems
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Prevents hydraulic fluid leakage at high-pressure interfaces
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Maintains proper system pressure for smooth and efficient operation
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Protects internal components from dirt, moisture, and contamination intrusion
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Supports long-term durability and consistent performance in turf equipment
Compatible With
The Hydro-Gear 55204 O-Ring is used in select Hydro-Gear hydrostatic systems, including:
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Hydro-Gear integrated transaxles
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Pump and motor assemblies requiring square-section sealing
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Transmission or hydraulic interfaces that specify a 137 (2.05 0.099) seal
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OEM parts diagrams and repair kits calling for part number 55204
Note: Always verify compatibility by cross-referencing your Hydro-Gear transmission or pump model with the official Hydro-Gear parts breakdown before ordering.
How Its Used
This square-profile O-ring installs between two mating components to create a fluid-tight seal:
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Remove old seal: Drain hydraulic fluid and clean the service area.
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Clean surfaces: Ensure sealing surfaces are free of debris, nicks, or burrs.
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Lubricate O-ring: Lightly coat with hydraulic fluid or appropriate assembly lubricant.
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Install: Carefully seat the Hydro-Gear 55204 O-ring into its groove or sealing surface.
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Reassemble: Align and secure mating components per service instructions.
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Refill fluid: Refill with proper hydraulic fluid and test system operation.
Proper installation and surface preparation are key to effective sealing and leak prevention.
Suggested Maintenance
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Inspect hydraulic sealing areas during service intervals for fluid seepage
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Replace O-rings whenever related components are disassembled
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Keep hydraulic fluid clean to reduce premature seal wear
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Avoid using damaged or stretched O-rings during reassembly
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Use only OEM-spec Hydro-Gear seals for correct fit and long-lasting performance
The Hydro-Gear 55204 O-Ring (137, 2.05 0.099, Square Profile) is a dependable OEM-spec sealing solution designed to prevent leakage, maintain pressure, and support long-term performance in compatible Hydro-Gear hydrostatic transmissions and hydraulic assemblies.
