- Scope and safety first
- This covers replacing the front strut top mount (common “shock mount”) on Mazda3 models; rear shock mounts and some model-year variations differ — check which you have before starting.
- Safety: never work under a car supported only by a jack. Use rated jack stands on a flat surface, wheel chocks, and eye protection. Compressing coil springs is hazardous — if you are a beginner, strongly consider buying a complete, preassembled strut (strut cartridge with spring and mount) to avoid using a spring compressor.

- How to identify the part you’re replacing
- Front: strut assembly with coil spring and top mount in the engine bay above the wheel well; top mount often has 3 nuts holding it to the strut tower.
- Rear (if applicable): separate shock body with an upper mount inside trunk/liner or underbody — procedure differs and spring compressor often not required for some rear shocks.
- If the noise/vibration is at the top of the strut, it’s the strut mount. If the shock itself leaks or the ride is poor, you may need the whole shock/strut.

- Tools and detailed descriptions (how to use, why needed)
- Hydraulic floor jack
- Description: low-profile jack that lifts a corner or side of the car.
- How to use: position under manufacturer jacking point, pump handle to lift, do not crawl under the vehicle on the jack alone.
- Why needed: raises vehicle to remove wheel and access suspension.
- Jack stands (pair)
- Description: rated stands that support the car after lifting.
- How to use: place under a solid pinch weld or control arm support point, lower car onto stands, test stability before working.
- Why needed: safe support while you work.
- Wheel chocks
- Description: rubber or plastic wedges for wheels remaining on ground.
- How to use: place behind wheels on opposite axle.
- Why needed: prevents vehicle rolling.
- Lug wrench / breaker bar with appropriate socket
- Description: cross wrench or 3/8–1/2" breaker bar and sockets to break lug nut torque.
- How to use: break lugs slightly while car is on ground, remove fully once car is raised.
- Why needed: remove wheel.
- Socket set (metric) and ratchet (3/8" and/or 1/2")
- Description: various sizes (commonly 12mm, 14mm, 17mm, 19mm, 21mm depending on year).
- How to use: use correct-size sockets to avoid rounding bolts; ratchet for smaller fasteners.
- Why needed: remove strut-to-knuckle bolts, top mount nuts, sway bar link, etc.
- Torque wrench (click-type)
- Description: calibrated tool to tighten bolts to specified torque.
- How to use: set to specified ft-lb or Nm, tighten until click, re-check.
- Why needed: ensures fasteners are tightened correctly for safety and avoid stripped bolts.
- Spring compressor (coil spring compressor) — HIGH-RISK TOOL
- Description: two-clamp threaded compressors that compress the spring so the top nut can be removed safely.
- How to use: fit clamps opposite each other on the spring, tighten evenly and slowly until spring is safely compressed; never remove compressor until nut is installed and tightened.
- Why needed: to separate the strut and replace top mount if you are reusing the spring/strut body.
- Safety note: if you are not comfortable using this, buy a remanufactured or new complete strut assembly to avoid using a compressor.
- Impact wrench (optional)
- Description: pneumatic/electric tool that quickly breaks nuts/bolts.
- How to use: use with appropriate socket and care; do not rely on to torque final fasteners accurately.
- Why it helps: speeds removal of stubborn bolts like lower strut bolts.
- Pry bar and large flat screwdriver
- Description: leverage tools.
- How to use: pry suspension components loose after bolts are removed; take care not to damage rubber boots.
- Why needed: to separate control arm or pop knuckle free.
- Ball joint/tie-rod separator or pickle fork
- Description: tool to separate ball joints or tie rod ends from knuckle.
- How to use: wedge and tap to dislodge stud from tapered hole.
- Why needed: required on many cars to clear the strut from the knuckle.
- Hammer and rubber mallet
- Description: striking tools (rubber mallet less damaging).
- How to use: tap loose stuck parts; use rubber mallet to avoid damage.
- Why needed: free rusted bolts or seating of components.
- Penetrating oil (e.g., PB Blaster, WD-40 Specialist)
- Description: chemical to loosen rusted or seized bolts.
- How to use: spray on bolts, allow soak time before attempting removal.
- Why needed: prevents bolt rounding and makes removal easier.
- Safety gear: gloves, safety glasses, steel-toe shoes recommended
- How to use: wear at all times to protect hands, eyes, and feet.
- Shop manual or online repair manual (Haynes, Chilton, factory service manual)
- Description: provides model-year specific torque specs and removal order.
- How to use: reference for exact bolts, torque, and torque sequence.
- Why needed: Mazda3 torque numbers and fastener locations can vary by year.

- Replacement parts and reasons
- Strut top mount (strut mount + bearing)
- Why replace: worn mounts cause clunks, steering wander, elevated NVH, and bearing wear causes steering stiffness.
- Part to buy: OEM Mazda part or quality aftermarket strut mount specific to your year/engine; many mounts include integrated bearing.
- Complete strut assembly (recommended for beginners)
- Why: avoids spring compressor use and eliminates many failure points (mount, bearing, strut).
- Part to buy: aftermarket complete strut cartridge (Monroe, KYB, Bilstein remanufactured or OEM Mazda replacement).
- Dust boot and bump stop (often replaced with mount)
- Why: protect the strut shaft and ensure proper travel; cheap and advisable to replace if torn.
- Upper strut nut (may be included with new mount)
- Why: often one-time-use / may be damaged during removal; replace if required.
- Sway bar end links, lower control arm components (optional)
- Why: if worn, replace at same time since you’ll have the car apart; otherwise they will produce noise later.
- Note about replacing both sides
- Best practice: replace both front mounts or both complete struts at the same time to keep handling symmetrical.

- Step-by-step procedure overview (bullets only; follow service manual for exact details and torque specs)
- Prepare car: park on level ground, set parking brake, chock rear wheels, loosen front lug nuts slightly while car is on ground.
- Lift and support: raise front with floor jack at jacking point, place jack stands under subframe or specified support points, lower car onto stands, remove wheel.
- Expose strut top: open hood, locate the 3 (or appropriate number) nuts on the strut tower; spray penetrating oil.
- Support lower control arm: use a small jack under the control arm to support it so it won’t drop when strut is detached.
- Remove sway bar link and brake line brackets: unbolt sway bar end link from strut and any brake line/ABS sensor clips attached to strut body.
- Remove lower strut-to-knuckle bolts: remove the lower bolts/nuts that attach the strut to the steering knuckle; you may need a pickle fork or separator to free the ball joint.
- Remove top nuts: while supporting the strut (hold it from below or have the control-arm jack support), remove the top nuts in the engine bay; remove the strut assembly from car.
- If reusing spring/mount: safely compress the spring with the spring compressor per the compressor’s instructions, remove centre nut from strut shaft, swap the old mount for the new one (and bearing), reassemble and torque the center nut to spec.
- If using a complete strut assembly: no spring compressor needed — install the new assembly into the car.
- Reinstall strut: position strut into strut tower, finger-tighten top nuts to hold position, align lower strut with knuckle and reinstall lower bolts, reconnect sway bar link and brake line clips.
- Torque fasteners: set torque wrench to factory specs and torque top nuts, lower bolts, sway bar link per manual. Ensure all fasteners are torqued in correct sequence.
- Reinstall wheel: torque lug nuts to spec with car on ground or per lugs spec.
- Lower car safely: remove jack stands and lower car; re-torque lug nuts to final spec if necessary.
- Test and alignment: road test at low speed to ensure no noises; get a professional wheel alignment ASAP — changing strut assembly/top mount affects camber/caster and steering geometry.

- Important warnings and tips
- Do not rely on a single jack; always use jack stands.
- Spring compressors are dangerous if used incorrectly; uneven compression or a slipped clamp can release a spring violently — if unsure, buy a complete strut.
- Always replace mounts in pairs (both left and right) for balanced handling.
- Always use a torque wrench for critical fasteners (top nuts, lower bolts, lug nuts).
- After replacement, professional alignment is required to avoid uneven tire wear and poor handling.
- If bolts are rusted beyond safe reuse, replace them; do not reuse damaged fasteners.
- If the vehicle has specific corrosion protection or sensors (ABS sensor wiring) take care to reconnect and secure them.

- If you are a complete beginner — recommended path
- Buy complete front strut assemblies (both sides) specific to your Mazda3 year and engine; they come preassembled with spring, mount, and boot.
- Gather the basic tools: floor jack, pair of jack stands, wheel chocks, socket set, breaker bar, torque wrench, lug wrench, penetrating oil, pry bar, safety gear.
- Follow the steps above, avoid using a spring compressor, and take the car for a professional alignment after installation.

- Final notes
- Exact bolt sizes and torque values vary by model year; obtain the Mazda factory service manual or a trusted repair guide for your exact year before attempting work.
- If you prefer not to do this yourself, a small independent shop can replace struts and mounts and do the alignment — expect to pay for labor and alignment.


rteeqp73

Mazda3 | Owner's Manual | Driving Position

2021 Mazda3 Turbo AWD Hatchback - Watch Out WRX! The 2021 Mazda Mazda3 hatchback is now available with all-wheel drive and a turbo-charged 2.5-liter engine. Is this the Subaru ...

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