🔧 Mazda3 - Shock Absorber/Strut Replacement

On your Mazda3, the rear uses separate shock absorbers, and the front uses strut assemblies (a strut is a shock with a spring mounted on it). Replacing worn shocks/struts restores ride control, reduces bouncing, and helps braking/handling stay stable.

Difficulty Level: Advanced | Estimated Time: 3-6 hours

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⚠️ Safety & Precautions

• ⚠️ Never work under a car supported only by a jack—use jack stands on solid ground.
• ⚠️ Front struts contain a compressed spring—only use a spring compressor (a tool that safely compresses the coil spring) and keep hands/face out of the spring’s path.
• ⚠️ Support the suspension arm/knuckle so you don’t overstretch the brake hose or ABS wire.
• ⚠️ If you remove front struts, you should get a 4-wheel alignment afterward.
• 🔋 Battery disconnect is not required for this job.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Safety glasses
• Mechanic gloves
• Breaker bar
• Torque wrench (20–200 ft-lbs range)
• 21mm socket
• 19mm socket
• 17mm socket
• 14mm socket
• 10mm socket
• Ratchet
• Socket extensions (3" and 6")
• Combination wrench set (10mm–19mm)
• 5mm Allen key
• Flat trim tool
• Rubber mallet
• Penetrating oil
• Paint marker
• Spring compressor (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Rear shock absorbers - Replace in pairs - Qty: 2
• Rear upper shock mounts/isolators - Replace in pairs - Qty: 2
• Front struts - Replace in pairs - Qty: 2
• Front strut mounts/bearing plates - Replace in pairs - Qty: 2
• Front bump stops and dust boots - Replace in pairs - Qty: 2
• New self-locking nuts/bolts (strut/shock hardware kit) - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and place wheel chocks behind the rear tires if lifting the front (and in front of the front tires if lifting the rear).
• Use a 21mm socket to loosen lug nuts 1/2 turn before lifting.
• Spray penetrating oil on the lower shock/strut bolts and sway bar link nuts and let it soak for 5–10 minutes.
• If doing the front struts, plan for an alignment after the repair.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Lift and remove wheels

• Use a floor jack to lift the end of the car you’re working on.
• Set the car down onto jack stands at the factory jack points.
• Remove the wheels using a 21mm socket.

Step 2 (Rear): Remove the rear shock lower bolt

• Place the floor jack lightly under the rear lower control arm to support it.
• Remove the lower shock bolt using a 17mm socket and breaker bar.
• Keep the arm supported so it doesn’t drop.

Step 3 (Rear): Access and remove the rear shock upper nuts

• Open the trunk.
• Use a flat trim tool to carefully remove the side trunk liner fasteners near the shock tower area.
• Remove the shock upper nuts using a 14mm socket and extension.
• Remove the shock from the wheel well.

Step 4 (Rear): Install the new rear shock

• Move any mounts/isolators to the new shock (or install new mounts if you bought them).
• Position the new shock and start the upper nuts by hand using a 14mm socket.
• Line up the lower mount and install the lower bolt using a 17mm socket.
• Tighten the upper nuts with a torque wrench: Torque to 39–54 Nm (29–40 ft-lbs)
• Tighten the lower bolt with a torque wrench: Torque to 69–93 Nm (51–69 ft-lbs)

Step 5 (Front): Remove the sway bar end link from the strut

• Hold the end link stud with a 5mm Allen key if it spins.
• Remove the nut using a 14mm socket or 14mm wrench (varies by hardware).

Step 6 (Front): Remove the strut-to-knuckle bolts

• Use a paint marker to mark the strut-to-knuckle position as a reference.
• Support the knuckle area lightly with the floor jack.
• Remove the two large lower bolts/nuts using a 17mm socket and 19mm socket with a breaker bar.
• Tap bolts out gently with a rubber mallet if needed.
• Don’t let the knuckle hang by the hose.

Step 7 (Front): Remove the strut top nuts and remove the strut

• Open the hood.
• Remove the strut mount nuts using a 14mm socket and extension.
• Pull the strut assembly out through the wheel well.

Step 8 (Front): Swap spring onto the new strut (if not using complete assemblies)

• Install the spring compressor (specialty) on opposite sides of the spring and compress evenly until the spring is loose in the mount.
• Remove the strut shaft top nut using a socket and wrench as needed (hardware varies).
• Transfer the spring, bearing/mount, bump stop, and boot to the new strut.
• Reinstall the top nut, then slowly and evenly release the spring compressors.

Step 9 (Front): Install the strut and tighten fasteners

• Set the strut into the tower and hand-start the top nuts using a 14mm socket.
• Install the strut-to-knuckle bolts using a 17mm and 19mm setup.
• Reconnect the sway bar end link using a 14mm socket and 5mm Allen key if needed.
• Tighten the strut-to-knuckle bolts with a torque wrench: Torque to 98–127 Nm (72–94 ft-lbs)
• Tighten the sway bar end link nut with a torque wrench: Torque to 44–59 Nm (33–43 ft-lbs)
• Tighten the strut top nuts with a torque wrench: Torque to 39–54 Nm (29–40 ft-lbs)

Step 10: Reinstall wheels and set the car down

• Reinstall wheels and hand-thread lug nuts using a 21mm socket.
• Lower the car off the jack stands using the floor jack.
• Tighten lug nuts in a star pattern with a torque wrench: Torque to 108–118 Nm (80–87 ft-lbs)

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✅ After Repair

• Take a short, slow test drive and listen for clunks over small bumps.
• Recheck all visible fasteners for tightness after the test drive.
• If you replaced front struts, schedule a 4-wheel alignment as soon as possible.
• If the ride height looks uneven, confirm springs are seated correctly in the mounts.

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💰 DIY vs Shop Cost

Shop Cost: $800-$1,800 (parts + labor)

DIY Cost: $250-$900 (parts only)

You Save: $550-$900 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 3-6 hours.

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🎯 Ready to get started?

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