TOYOTA 90105-13010 Flywheel Flange Bolt

The genuine TOYOTA 90105-13010 is a premium-quality, high-strength flywheel mounting flange bolt (BOLT, FLANGE). This specialized fastener plays a critical role in the vehicle's powertrain system, ensuring a stable and secure attachment of the flywheel to the crankshaft.

Technical Features and Specifications

Flywheel bolts are subjected to extreme shear and tensile stresses, as well as continuous vibration. Consequently, they are manufactured to TOYOTA's rigorous factory standards:

• Material Quality: High-tensile, hardened steel alloy engineered to withstand dynamic mechanical loads and high operating temperatures.
• Head Design: Flanged head configuration that distributes clamping force evenly across the contact surface, eliminating the need for an additional washer.
• Surface Treatment: Specialized anti-corrosion and friction-modifying coating that ensures precise and repeatable tightening torque during installation.
• Installation Recommendation: Because flywheel bolts are typically tightened to their elastic limit (torque-to-yield/stretch bolts), manufacturer guidelines mandate replacing them with brand-new bolts every time the assembly is disassembled.

Function and Importance

The flywheel transmits engine torque through the clutch assembly to the transmission. The primary role of the mounting bolts is to transfer this immense torque securely and without backlash. Using inferior, damaged, or reused bolts can lead to flywheel loosening, damage to the crankshaft flange, or catastrophic engine and transmission failure.

Signs of Wear or Metal Fatigue

• Thread Damage or Elongation: Detectable upon visual inspection following bolt removal (uneven thread pitch).
• Increased Vibration: If the bolts stretch or loosen, minimal axial play of the flywheel can transmit severe vibration through the clutch pedal and engine block.
• Abnormal Noises: Metallic knocking or rattling sounds originating from the clutch bellhousing area, particularly during load transitions or engine startup.