M83248/1-008 - Fluorocarbon Rubber O-Ring, 3/16 in ID 5/16 in OD 1/16 in Thick

M83248/1-008 – Fluorocarbon (Viton™) High-Performance O-Ring

Available now through the AirParts Aero marketplace.

Overview Section

The M83248/1-008 is an aerospace-standard Fluorocarbon (FKM/Viton™) O-Ring designed for high-temperature and chemically aggressive environments.1 This specific part is manufactured to the MIL-R-83248 military specification (specifically Type 1, Class 1), ensuring it meets the most rigorous standards for fluid resistance and thermal stability in aviation and defense applications.2

As a -008 dash size (per AS568 standards), this O-ring is frequently used in fuel system components, hydraulic fittings, and engine sensors where a reliable seal is required under extreme conditions. The Fluorocarbon material is chosen for its ability to maintain its sealing "memory" and elasticity far longer than standard Nitrile (Buna-N) when exposed to modern synthetic lubricants and high-octane fuels.

This part superscedes part number: MS9388-009

Key Features Section

• Extreme Temperature Range: Reliably maintains a seal from -15°F to +400°F ($-26°C$ to $+204°C$), making it ideal for engine nacelles and hot-section fluid lines.

• Superior Chemical Resistance: Highly resistant to a wide spectrum of fluids including Jet-A, 100LL, Skydrol (certain types), synthetic turbine oils, and various hydraulic fluids.

• 75 Durometer (Shore A): Offers the optimal balance of hardness and flexibility, providing enough "squeeze" to seal low-pressure systems while remaining stiff enough to resist extrusion in higher-pressure fittings.3

  
  

  
  

• Compression Set Resistance: Engineered to resist permanent deformation, ensuring the seal remains effective even after long periods of compression in a static gland.

• Ozone and UV Immunity: Unlike organic rubbers, the M83248/1 material is virtually unaffected by ozone and weather, making it suitable for external airframe applications.

• Precision AS568 Sizing: Manufactured to the -008 standard, ensuring a perfect fit in any gland designed for these specific dimensions.

Technical Specifications Section

Aircraft Compatibility Section

The M83248/1-008 is a ubiquitous sealing component found across almost every aircraft platform in the AirParts Aero inventory:

• Beechcraft King Air / 1900: Used in fuel injector seals and engine-driven pump interfaces.

• Cessna Citation Series: Found in hydraulic manifold port seals and environmental control system valves.

• Piper / Cessna Piston Aircraft: Standard seal for fuel strainer bowls, quick-drain valves, and oil temperature sensor probes.

• Turbine Engines (PT6, TFE731): Utilized for external oil line fittings and accessory mounting pads.

Technical Applications & Safety

The M83248/1-008 is often used in Static applications (where parts do not move relative to each other) but can also be found in Dynamic applications (like valve stems) provided the surface finish of the mating part is within aerospace tolerances.

Safety Warning: Never substitute an M83248/1 (Fluorocarbon) O-ring with a standard MS28775 (Nitrile) O-ring in a high-heat or fuel-carrying system. While they may look identical, a Nitrile O-ring will swell, soften, and eventually fail if exposed to high temperatures or certain synthetic oils, leading to critical fluid leaks. Always verify the part number on the "Green Label" or vacuum-sealed packaging before installation.

Maintenance Insight

The engineering value of the M83248/1-008 lies in its Chemical Inertness. Because modern aviation fluids contain complex additives for lubrication and anti-corrosion, seals made from lesser materials often "leach" chemicals, causing the seal to shrink or crack. The M83248/1-008 maintains its molecular structure even in the presence of aggressive aromatics.

By sourcing your seals through AirParts Aero, you ensure that the O-rings have not exceeded their Cure Date (shelf life). While Fluorocarbon has a very long shelf life (often 20+ years), "fresh" seals are always preferred to ensure maximum pliability during the initial installation "stretch."

Installation & Maintenance Addendum

1. Lube Requirements: Always use an approved lubricant, such as Parker O-Lube or a thin film of the system fluid (e.g., clean engine oil), to prevent the O-ring from "twisting" or "spiraling" as the fitting is torqued.

2. Tool Safety: Use only plastic or brass O-ring picks for removal and installation. Steel tools can scratch the aluminum gland surface, creating a "leak path" that no new O-ring can fix.

3. Stretch Limits: Do not stretch the O-ring more than 50% of its ID during installation, as this can cause microscopic surface fractures in the Fluorocarbon material.