TOYOTA 91551-80625 Flange Bolt

The genuine TOYOTA flange bolt with part number 91551-80625 (BOLT, FLANGE) is a premium-quality factory fastener specifically designed for the secure fastening of vehicle structural and mechanical assemblies. Thanks to the integrated flange design, the collar beneath the bolt head evenly distributes clamping force across the mating surface, providing maximum hold without the need for a separate washer while protecting the fastened components from surface damage.

Technical Characteristics and Specifications

• Manufacturer: TOYOTA (Original Equipment Manufacturer - OEM)
• Part Number: 91551-80625
• Type: Hex flange bolt
• Material: High-tensile, hardened steel alloy offering exceptional resistance to shear and tensile stresses.
• Surface Treatment: Specialized anti-corrosion coating (galvanized or phosphated layer) that protects the bolt against moisture, road salt, and chemicals.
• Thread Design: Precision metric thread ensuring a perfect fit with factory thread profiles.

Function and Importance of the Flange Bolt

Flange bolts play a critical role in various automotive systems where continuous vibration and thermal cycling create a risk of loosening. The integrated flange increases the bearing surface area, thereby reducing surface pressure and preventing the bolt from backing out. It is most commonly applied in the engine bay, auxiliary equipment mounting brackets, specific suspension points, and body panel assemblies.

Signs of Wear, Deterioration, or Damage

Although genuine Toyota bolts are engineered for high durability, replacement may become necessary under certain conditions. The most common symptoms of failure include:

• Thread damage or elongation: Over-torquing or improper installation can deform the threads or stretch the bolt shank, compromising clamping load.
• Severe corrosion: Rust forming after damage to the protective coating weakens the bolt material, which can eventually lead to fracture.
• Damaged bolt head: The use of incorrect or worn tools can round the corners of the hex head, making safe tightening or removal difficult or impossible.

To ensure safe and reliable vehicle operation, loose, deformed, or corroded fasteners should always be replaced with genuine OEM parts, strictly adhering to factory-specified tightening torques.