MS28775-012 – Military Standard Synthetic Rubber Hydraulic O-Ring Packing Seal
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Overview
The MS28775-012 is a military-standard, preformed packing O-ring engineered for high-performance sealing in aerospace fuel, oil, and hydraulic systems. Manufactured in strict accordance with military specifications (such as MIL-R-83248), this O-ring is made from a high-quality Fluorocarbon (FKM) synthetic rubber, commonly known by the trade name Viton®. This material is specifically chosen for its excellent resistance to a wide range of petroleum-based and synthetic fluids, and its ability to maintain sealing integrity at elevated temperatures where standard Nitrile seals would degrade and fail.
Key Features
- High-Temperature Fluorocarbon (FKM) Material: Fabricated from a Viton® (FKM) elastomer, providing superior performance in high-temperature environments and excellent resistance to petroleum-based oils, jet fuels, and most hydraulic fluids.
- Excellent Fluid Resistance: Offers low swell and resistance to degradation when exposed to a wide array of chemicals, ensuring a durable, long-lasting seal in aggressive fluid systems.
- MS Certified Standard: As a certified MS28775 part, it guarantees that the material compound, physical properties (like durometer and compression set), and dimensional tolerances meet the highest standards for aviation safety and reliability.
- Precision Dimensions: The "-012" dash number corresponds to a specific dimensional standard (AS568), which ensures a perfect fit into glands designed for this O-ring size, providing a reliable seal under system pressure.
- Versatile Application: A widely used seal in countless components across numerous aircraft platforms, from general aviation to commercial and military jets.
Technical Specifications
- Standard: MS28775 / MIL-R-83248 Type I
- Full Part Number: MS28775-012
- Material: Fluorocarbon Synthetic Rubber (FKM / Viton®)
- Durometer (Hardness): 75 Shore A
- Color: Black
- AS568 Dash Size: -012
- Precise Dimensions:
- Inside Diameter (I.D.): 0.362 inches
- Outside Diameter (O.D.): 0.568 inches
- Cross Section (C.S.): 0.103 inches
- Operating Temperature Range: Approximately -15°F to 400°F (-26°C to 204°C)
- Primary Fluid Compatibility: Petroleum-based oils, fuels (Jet A, 100LL), and hydraulic fluids (MIL-H-5606, MIL-H-83282).
Aircraft Compatibility
The MS28775-012 O-ring is a standard seal used in numerous applications across the entire spectrum of aviation. Its use is determined by the specific requirements of the component it seals.
- Common Applications:
- Fuel Systems: Used as seals in fuel pumps, fuel control units (FCUs), and fuel line fittings where high-temperature resistance is required.
- Engine & Powertrain: Serves as a critical seal in lubrication systems, propeller hubs, and accessory gearbox housings that experience high operating temperatures.
- Hydraulic Systems: Utilized in hydraulic pumps, actuators, and valves, especially in systems using fire-resistant hydraulic fluids or operating at higher temperatures.
Applications
The MS28775-012 is the engineered sealing solution where standard Nitrile O-rings would fail:
- High-Temperature Sealing: Its primary application is in joints that must maintain a reliable seal at continuous operating temperatures up to 400°F.
- Aggressive Fluid Sealing: Provides a durable, long-term seal in constant contact with aromatic hydrocarbons and synthetic fluids that would quickly degrade other elastomers.
- Static & Dynamic Sealing: Suitable for use in both static face seals (e.g., flanges) and dynamic reciprocating seals (e.g., pistons).
Why Choose MS28775-012?
Choosing the correct O-ring material is critical for flight safety. An O-ring failure can lead to a catastrophic leak of fuel, oil, or hydraulic fluid. The MS28775-012, made from Fluorocarbon (FKM), is specifically designed to perform in high-temperature and chemically aggressive environments where a standard Nitrile (Buna-N) O-ring would harden, crack, and fail. Using a genuine, certified MS-standard part is the only way to ensure the O-ring has the correct, tested material properties for the demanding conditions of flight.
Order Your MS28775-012 O-Rings Now
Ensure the integrity of your aircraft's most critical fluid systems with certified, high-performance seals. Visit Airparts.aero to order your MS28775-012 O-rings today.
The material science of the MS28775-012 O-ring sets it apart. Fluorocarbon (FKM) is a fluoroelastomer with a high fluorine content. The carbon-fluorine bonds in its molecular structure are extremely strong and stable, which gives the material its exceptional resistance to heat, oxidation, and chemical attack. This makes it the material of choice for sealing applications "firewall forward" and in high-performance hydraulic systems. While it does not have the extreme low-temperature flexibility of Fluorosilicone (M25988), its superior high-temperature performance and physical toughness make it the standard for a majority of high-performance fuel and oil sealing applications in aviation.
Note: This is a flight-critical sealing component. Always verify the correct O-ring part number from the applicable component maintenance manual (CMM) or aircraft Illustrated Parts Catalog (IPC). Ensure the O-ring is within its specified shelf life before installation. Lubricate with a clean, compatible system fluid to prevent damage during assembly.