TOYOTA 90105-10017 Alternator Mounting Flange Bolt

The genuine OEM part Toyota 90105-10017 is a premium-quality washer-based flange bolt designed primarily for the secure, vibration-resistant mounting of the alternator and its supporting brackets. This high-tensile fastener plays a critical role in the stable positioning of auxiliary components, minimizing the risk of loosening caused by dynamic loads during engine operation.

Function and Importance

The alternator mounting bolt is engineered to withstand continuous engine vibration, serpentine belt tension, and high temperature fluctuations within the engine bay. The integrated washer (flange) design evenly distributes clamping force across mating surfaces, preventing component deformation and ensuring maximum joint integrity without requiring a separate washer.

Technical Specifications

• Type: Hex flange bolt (Bolt, Washer Based)
• Material Quality: High-tensile, hardened steel alloy engineered to withstand maximum shear and tensile loads
• Surface Treatment: Specialized corrosion-resistant coating (zinc-plated or phosphated) providing protection against moisture, road grime, and engine bay chemicals
• Application: Alternator mounting, tensioner brackets, and other heavy-duty engine bay auxiliary equipment fastening

Signs of Wear or Failure

Replacement of the mounting bolt is recommended in the following cases:

• Thread damage or stretching: Often the result of improper tightening torque (over-torquing).
• Structural corrosion: Surface rust weakens the material, potentially leading to fracture.
• Loosening: If the bolt loses its clamping force, alternator alignment may shift, causing premature serpentine belt wear, belt failure, or noisy operation.

Note: Always adhere to the manufacturer's specified torque specifications during installation to protect threads and mating castings.