Genuine Mazda Engine Mount & Suspension Arm Locking Nut • 8871-34-222

Genuine Mazda Engine Mount & Suspension Arm Locking Nut

Replacement Genuine Mazda locking flange nut for Mazda MX-5 Mk1 NA and Mk2/Mk2.5 NB models, with applications across the engine side mounts and selected suspension-arm mounting bolts.

This K-nut-style fastener incorporates a locking feature designed to resist loosening after installation. Mazda uses the same nut in several safety-critical mounting positions where a secure, vibration-resistant threaded connection is required.

On all Mk1 and Mk2/Mk2.5 MX-5 models, the nut is used on the engine side-mount assemblies. Four nuts are fitted across the two engine mounts. It is also used on selected lower suspension-arm bolts: the front lower arms on 1994–1998 Mk1 models, and the front and rear lower arms on Mk2 and Mk2.5 models.

Important replacement advice: This is a prevailing-torque, one-use-style locking nut. Mazda locking nuts should not normally be reused after removal because their locking performance can be reduced.

• Part type: Locking flange nut
• Common names: K-nut / self-locking nut / engine-mount nut / suspension-arm nut
• Mazda catalogue description: Nut / flange nut
• Confirmed engine-mount location: Engine side mounts
• Confirmed suspension location: Selected front and rear lower suspension-arm bolts
• Locking design: Prevailing-torque K-nut style
• Quantity used on engine side mounts: 4 per vehicle
• Suspension quantity: Varies by mounting position and repair
• Quantity supplied: 1 nut
• Mounting bolt included: No
• Washer included: No
• Engine mount included: No
• Suspension arm included: No
• Brand: Genuine Mazda
• Part No.: 8871-34-222

Confirmed MX-5 applications:

• Engine side mounts: All Mk1 NA and Mk2/Mk2.5 NB models
• Front lower suspension-arm bolts: Mk1 NA, 1994–1998
• Front and rear lower suspension-arm bolts: Mk2 and Mk2.5 NB/NB-FL, 1998–2005

Typical reasons for replacement:

• Nut removed during engine-mount replacement
• Suspension arm or bush replacement
• Locking feature weakened through previous use
• Threads corroded or damaged
• Nut rounded or distorted during removal
• Original fastener missing
• Previously fitted non-locking or incorrect hardware

Fitment advice: The same nut is used in multiple positions, but the required quantity depends on the repair being carried out. Identify every mounting position being dismantled and order the corresponding number of replacement nuts.

Engine-mount quantity advice: Four nuts are used across the engine side-mount assemblies. This listing supplies one nut per order quantity.

Suspension advice: Suspension geometry can be affected whenever a control-arm mounting bolt is loosened or removed. Mark the original cam-bolt positions where applicable and arrange a full wheel-alignment check after reassembly.

Replacement advice: Inspect the corresponding bolt threads, washers, mounting brackets, engine mounts, suspension-arm bushes and cam plates before assembly. A new nut will not correct damaged bolt threads, elongated mounting holes or failed rubber bushes.

Other items to consider: When working on the engine mounts, inspect both rubber mounts, mounting brackets and associated washers and bolts. During suspension repairs, inspect the control-arm bushes, ball joints, cam plates and adjustment bolts.

Useful tools / consumables: Socket and spanner set, calibrated torque wrench, penetrating fluid, wire brush, thread-cleaning tools, vehicle support equipment and wheel-alignment equipment following suspension work.

Difficulty guide: DIY Difficulty: Moderate. Engine-mount work requires the engine to be safely supported. Suspension-arm work may involve seized hardware and requires correct vehicle support and subsequent alignment.

Why Genuine Mazda? Genuine Mazda locking nuts match the original thread specification, flange profile, strength class and prevailing-torque characteristics required for the corresponding mounting hardware. Correct locking fasteners are particularly important on engine and suspension components exposed to vibration and repeated loading.

What’s in the box: One Genuine Mazda locking flange nut, part number 8871-34-222.

Installation notes: Safely support the engine or vehicle component before removing the original fastener. Clean and inspect the corresponding bolt threads and mounting surfaces. Install the new nut by hand initially to prevent cross-threading, then tighten it using the applicable Mazda procedure. Do not lubricate the threads unless instructed by the relevant workshop procedure, as this can alter the achieved clamping load. Replace rather than reuse the locking nut following future removal.