Before You Start / Safety
- Flat surface, handbrake on, wheels chocked.
- If lifting car, use stands under correct support points.
- Keep fingers clear when jouncing suspension.
Required Tools
- Flashlight
- Clean rag/paper towel
- Jack + axle stands (optional but recommended)
- Tire pressure gauge (to avoid false symptom diagnosis)
Required Parts / Fluids
- None for inspection-only work
- If faults found: shocks, bump stops, dust boots, and top mounts as needed
NB suspension orientation quick guide
- Front dampers are inside spring/shock assemblies at each front corner.
- Rear dampers are mounted through rear suspension towers.
- On many aging NB cars, dust boots and bump stops degrade before visible oil leaks appear.
Step-by-Step Procedure
1) Baseline road symptom check
On a familiar route, note if the car shows:
- repeated bounce after speed bumps,
- front dive under braking,
- rear float/wallow on highway undulations,
- extra body roll versus normal feel.
2) Tire and alignment sanity check first
Set pressures to target values before judging damper behavior. Incorrect pressure or severe toe error can mimic bad shocks.
3) Static bounce/jounce test by corner
Push body down firmly at each corner and release:
- healthy damping: one rise and settle,
- weak damping: repeated oscillation.
Use this as a quick indicator, not the only decision tool.
4) Visual shock body/shaft inspection
Check each damper for:
- oil wetness running down body,
- dirt stuck to oily film (persistent leak sign),
- shaft pitting/rust,
- dented shock body,
- torn/missing dust boot.
A light “mist” near seal can be normal aging; active wet streaking indicates replacement is near/needed.
5) Mount and bushing check
Inspect upper/lower mounts for:
- cracked rubber,
- collapsed bushing shape,
- metal-to-metal contact clues,
- clunk when wheel is moved up/down.
6) Replace-vs-monitor decision
Plan replacement when one or more are true:
- active oil leakage,
- repeated oscillation on jounce test,
- clear handling degradation not explained by tires/alignment,
- mount/bushing failure causing noise/play.
Replace in axle pairs (front pair or rear pair) at minimum to keep damping balanced.
Verification / Post-service checks
- No fluid seep visible after short drive
- No clunk from mounts over small bumps
- Predictable body control in braking/turn-in
- Recheck tires for abnormal wear progression after several weeks
Sources
- MELLENS — Mazda Miata factory service manual archive (NB suspension reference index). Retrieved 2026-03-01. https://www.mellens.net/mazda/
- BOFI Racing — MX-5/Miata workshop manual index (NB year-specific documentation path). Retrieved 2026-03-01. https://bofiracing.com/blog/mx5-miata-workshop-manuals/
- AutoZone — Shock/strut symptom guide (body-control symptom context and safety rationale). Retrieved 2026-03-01. https://www.autozone.com/diy/shocks-and-struts/symptoms-of-bad-shocks-and-struts
- Miata.net Forum — NB owner context on shock choices and ride-control behavior changes. Retrieved 2026-03-01. https://forum.miata.net/vb/showthread.php?t=799338