Genuine Mazda Rear Upper Lateral Arm Mounting Nut • 9YB0-41-215

Genuine Mazda 9YB0-41-215 Rear Upper Lateral Arm Mounting Nut

Replacement Genuine Mazda rear suspension mounting nut for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC models.

This nut secures the outer end of the upper rear lateral suspension arm to the rear wheel knuckle. The lateral arm helps locate the rear wheel assembly and control its position as the suspension moves.

This is the smaller of the two nuts found at the upper lateral-arm-to-knuckle mounting area. It should not be confused with the larger nut used on the adjacent suspension fastening arrangement.

There are two fitted per vehicle, one on each side of the rear suspension. This listing supplies one Genuine Mazda nut, so select a quantity of two when replacing both sides.

Replacement should be considered where the original nut is heavily corroded, seized, rounded, cross-threaded, missing or no longer provides the intended locking resistance.

• Part type: Rear upper lateral arm mounting nut
• Primary use: Secures the upper rear lateral arm to the wheel knuckle
• Location: Outer upper rear lateral-arm mounting point
• Position note: Smaller of the two nuts at the knuckle connection
• Quantity fitted per vehicle: 2
• Quantity supplied: 1 nut
• Brand: Genuine Mazda
• Part No.: 9YB0-41-215
• Also referenced as: 9YB041215
• MX-5 fitment: Mk3, Mk3.5 and Mk3.75 NC models

Fitment advice: This nut is intended for the upper rear lateral-arm-to-knuckle fastening position. Several visually similar nuts are used throughout the NC rear suspension, so match the original mounting position and Mazda part number before installation.

Other items to consider: Inspect the associated suspension bolt, upper lateral arm, arm bush, wheel-knuckle mounting bore and the corresponding fastener on the opposite side. Replace any bolt with damaged, stretched or heavily corroded threads.

Useful tools / consumables: Suitable socket and spanner set, breaker bar, penetrating fluid, calibrated torque wrench, wire brush, suspension support equipment and wheel-alignment equipment where the suspension geometry has been disturbed.

Difficulty guide: DIY Difficulty: Moderate. The suspension arm and wheel knuckle should be supported correctly before loosening the fastener. Final tightening may need to be carried out with the suspension at its normal ride position to avoid preloading the suspension bush.

Why Genuine Mazda? Genuine Mazda suspension hardware is manufactured to match the original thread, nut dimensions, strength specification and locking characteristics required by the rear suspension assembly. Correct hardware helps maintain the specified clamping force and compatibility with the original suspension bolt and knuckle.

What’s in the box: One Genuine Mazda rear upper lateral arm mounting nut, part number 9YB0-41-215.

Installation notes: Support the rear suspension safely before loosening the mounting hardware. Clean and inspect the bolt threads and mounting faces, then start the new nut by hand to prevent cross-threading. Tighten the fastener to the applicable Mazda workshop specification, with the suspension positioned as required by the repair procedure. Check rear-wheel alignment after installation if the suspension arm position has been disturbed.