Genuine Mazda Front Subframe Mounting Nut – MX-5 Mk3 / NC • 9YB04-1406A

Genuine Mazda 9YB04-1406A Front Subframe Mounting Nut

Replacement Genuine Mazda front subframe mounting nut for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 / NC models with applicable 1.8L and 2.0L petrol engines listed in the compatibility table.

The nut threads onto one of the main chassis studs used to secure the front suspension subframe to the vehicle body.

Correct clamping at this connection helps maintain the intended position and rigidity of the front subframe, steering rack, engine mounting and front suspension assemblies.

Replacement may be required if the original nut is corroded, seized, rounded, damaged or lost during front-subframe, suspension, steering or engine repair work.

Mazda specifies two of these nuts per applicable MX-5. This listing supplies one individual nut.

• Part type: Front subframe mounting nut
• Mazda catalogue description: Nut
• Alternative descriptions: Front crossmember nut / front suspension subframe nut / chassis-stud nut
• Primary function: Secures the front subframe to a main chassis mounting stud
• System: Front chassis and suspension structure
• Fitting position: Front subframe-to-body mounting point
• Primary vehicle application: Mazda MX-5 Mk3, Mk3.5 and Mk3.75 / NC
• Engine applications: Applicable 1.8L and 2.0L petrol models
• Transmission applications: Manual and automatic according to vehicle specification
• Fastener type: Flanged mounting nut
• Quantity required per vehicle: Two
• Quantity supplied: One individual nut
• Brand: Genuine Mazda
• Part No.: 9YB04-1406A
• Also referenced as: 9YB041406A

Typical reasons for replacement:

• Front subframe removed or loosened
• Original nut corroded or seized
• Hexagon rounded during removal
• Threads damaged or contaminated
• Flange distorted or damaged
• Nut lost during repair work
• Front subframe or chassis-stud repairs being undertaken
• Suspension, steering or engine work requiring subframe removal

Fitment advice: This nut is used at the main chassis-stud mounting points for the front subframe on applicable Mazda MX-5 NC models.

Quantity advice: Two nuts are required per vehicle. Order two individual units when replacing both applicable front subframe mounting nuts.

Position advice: The MX-5 front subframe uses several different bolts, nuts and locating components. Confirm that the required fastener is the chassis-stud nut referenced as 9YB04-1406A.

Single-use advice: Where Mazda specifies replacement after removal, do not reuse the original locking nut. Repeated installation can reduce the effectiveness of its prevailing-torque or locking feature.

Thread advice: Inspect the chassis stud carefully before fitting the replacement nut. Do not force the nut onto damaged, dirty or cross-threaded threads.

Corrosion advice: Remove loose corrosion and contamination from the surrounding mounting area. Investigate significant corrosion affecting the stud, chassis or subframe before reassembly.

Alignment advice: Correctly support and align the front subframe before tightening its mounting fasteners. Tightening against a displaced or unsupported subframe can damage the threads or mounting structure.

Torque advice: Tighten the nut to the specification and sequence stated in the applicable Mazda workshop procedure. Do not estimate the final tightening torque.

Geometry advice: Removing or repositioning the front subframe can affect steering-wheel position and suspension geometry. Check wheel alignment after major subframe or suspension work.

Inspection advice: Inspect the remaining front subframe fasteners, mounting studs, locating points, suspension-arm mountings and steering-rack fixings while access is available.

Other items to consider: Consider inspecting or replacing the corresponding nut on the opposite side, associated subframe bolts, locating plates and any disturbed suspension or steering fasteners according to their condition.

Useful tools / consumables: Suitable socket and breaker bar, penetrating fluid, torque wrench, thread-cleaning tools and safe vehicle- and subframe-support equipment.

Difficulty guide: DIY Difficulty: Advanced when used during subframe removal. The vehicle and subframe must be supported safely, and all disturbed fasteners must be tightened correctly.

Why Genuine Mazda? Genuine Mazda chassis fasteners are manufactured to the intended thread, flange dimensions, material grade and locking specification. Using the correct OE nut helps preserve the original clamping arrangement at this safety-critical structural connection.

What’s in the box: One Genuine Mazda front subframe mounting nut, part number 9YB04-1406A. Two are required per applicable MX-5. Chassis stud, subframe, bolts, washers and installation tools are not included unless specifically shown or stated separately.

Installation notes: Safely raise and support the vehicle and support the front subframe before loosening its mounting hardware. Clean and inspect the chassis-stud threads and ensure the subframe is correctly positioned. Start the replacement nut by hand to prevent cross-threading, then tighten it in the specified sequence and to the applicable Mazda torque. Check all disturbed steering, suspension and engine-mounting components before returning the vehicle to service.