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Strut top mount/bearing inspection & replacement

NB strut top mount/bearing inspection and replacement with spring-compressor safety, clunk diagnosis logic, and post-install alignment checks.

Difficulty
Expert
★★★★★
Est. Time
3-6 hours
Models
NB1 & NB2
Last Updated
2026-03-13

Before You Start / Safety

This guide is for Mazda MX-5 NB (1998-2005) only.

Top mount/bearing work typically involves spring preload. Use approved spring compressor tools and follow safe compression practice.

Warning: “When replacing struts, a spring compressor is needed to remove the spring from the strut.” https://www.autozone.com/diy

High-risk quote: “Use proper safety gear and follow all safety precautions.” https://www.autozone.com/diy

Manual-reference quote: Mellens indexes NB-era factory manuals (1999-2001 and 2005), so mount orientation, bearing/insulator stack order, and final torque values must be confirmed by year/VIN before assembly. https://www.mellens.net/mazda/index.html

Required Tools

  • Floor jack + rated jack stands
  • Socket/wrench set, breaker bar
  • Torque wrench
  • Approved spring compressor
  • Paint marker for orientation marks
  • PPE (eye/hand protection)

Required Parts / Fluids

  • Correct upper mount(s) and bearing(s) for NB axle position
  • Top nut and related self-locking hardware (as specified)
  • Dust boots / bump stops if worn

Model-specific notes (NB1 vs NB2)

NB1 (1998-2000)

  • Verify installed suspension package before ordering; mixed parts are common.

NB2 (2001-2005)

  • Upper mount compatibility and prior suspension changes are common forum topics; inspect what is currently installed before parts purchase.

Community quote: r/Miata search repeatedly surfaces “Upgrading to NB shocks and upper mounts” and similar top-mount fitment/clunk threads. https://www.reddit.com/r/Miata/search/?q=nb%20top%20mount%20clunk&restrict_sr=1

Step-by-Step Procedure

1) Confirm symptom source

Typical top-mount/bearing clues:

  • front or rear suspension clunk over sharp bumps,
  • steering-related creak/bind (front),
  • visible mount rubber separation,
  • abnormal strut shaft movement at mount.

Rule out sway links, ball joints, and loose damper hardware before condemning top mounts.

2) Pre-check and baseline

  • Record ride height and note side-to-side differences.
  • Mark current strut-to-knuckle orientation where relevant.
  • Check for uneven tire wear suggesting alignment issues.

3) Remove strut/damper assembly

  • Raise and support vehicle safely.
  • Remove wheel and free necessary links/brackets.
  • Remove upper/lower assembly fasteners in FSM order.

4) Compress spring and disassemble top stack

  • Compress evenly and verify spring is unloaded from seat.
  • Remove top nut and disassemble mount/bearing/isolator stack.
  • Keep all components in exact order for inspection comparison.

5) Inspect and replace components

Replace mount/bearing if any of the following are present:

  • torn/separated rubber,
  • rough or seized bearing rotation,
  • collapsed mount height,
  • metal-to-metal witness marks.

6) Reassemble and install

  • Rebuild stack in correct orientation.
  • Hand-start all fasteners.
  • Final-torque using FSM values and ride-height loading requirements where applicable.

7) Post-service checks

  • Road-test for clunk/creak elimination.
  • Recheck fasteners after initial drive.
  • Perform alignment check after suspension disassembly.

Torque Specs / Capacities (if applicable)

  • Upper mount/top nut/lower attachment torques: year/VIN FSM only
  • Ride-height-loaded tightening requirements: year/VIN FSM only

No universal publish-safe NB torque table is provided here.

Verification / Post-service checks

  • No clunk/knock over small sharp bumps
  • Smooth steering return without bind/noise
  • No visible mount movement under static bounce test
  • Alignment confirmed after repair

Uncertainty / Open Questions

  • Direct strut-top-mount-specific independent pages were limited/404 in this environment.
  • Community evidence was partly search/snippet level rather than full thread extraction.
  • Therefore numeric torque and stack-order details are intentionally FSM-gated.

Community confirmation quote: old.reddit NB top mount/clunk search context highlights repeated NA/NB FAQ guidance and directs owners toward Miata.net/MX5Nutz for deeper platform-specific diagnostics. https://old.reddit.com/r/Miata/search?q=nb+top+mount+clunk&restrict_sr=on

Image Credits

No reusable, clearly licensed NB-specific strut top mount/bearing diagrams were retrieved in this run.

Sources

  1. Mellens.net — Mazda Miata Factory Service Manuals. Retrieved 2026-03-13. https://www.mellens.net/mazda/index.html
  2. AutoZone — Advice & How-To’s. Retrieved 2026-03-13. https://www.autozone.com/diy
  3. Reddit r/Miata — Search: nb top mount clunk. Retrieved 2026-03-13. https://www.reddit.com/r/Miata/search/?q=nb%20top%20mount%20clunk&restrict_sr=1
  4. Reddit r/Miata (old.reddit) — Search: nb top mount clunk. Retrieved 2026-03-13. https://old.reddit.com/r/Miata/search?q=nb+top+mount+clunk&restrict_sr=on
  5. Reddit r/Miata — Search: nb strut top mount. Retrieved 2026-03-13. https://www.reddit.com/r/Miata/search/?q=nb%20strut%20top%20mount&restrict_sr=1
  6. 2CarPros — How to Replace a Brake Master Cylinder (general workshop sequencing context). Retrieved 2026-03-13. https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder