ATE 390479 Brake Master Cylinder to Brake Booster Seal O-Ring

The ATE 390479 is a precision-engineered rubber seal designed to create a vacuum-tight connection between the brake master cylinder and brake booster. This critical component prevents vacuum leaks that could compromise brake booster performance and overall braking efficiency.

Key Features:

• EPDM (ethylene propylene diene monomer) rubber construction for excellent brake fluid resistance
• Inner diameter: 41.5mm (1.63 inches)
• Outer diameter: 46.5mm (1.83 inches)
• Thickness: 2.5mm (0.098 inches)
• Precision-molded square-cut profile for superior sealing performance
• Designed to withstand continuous exposure to brake system vacuum and heat

This seal is a direct replacement for OEM part number 251 611 243 and crosses to multiple vehicle manufacturers' part numbers. The EPDM material provides excellent resistance to brake fluid, heat, and aging, ensuring long-lasting reliability. A worn or missing master cylinder seal can cause vacuum leaks, resulting in reduced brake booster assistance and a harder brake pedal. Regular replacement of this seal during brake system service helps maintain optimal braking performance.