🔧 340i - Strut Replacement

On your 340i, “struts” usually means the front MacPherson strut assemblies (shock + coil spring). The rear uses separate shocks (not a strut), so I’m including both: front struts and rear shocks so you can do a complete refresh.

Difficulty Level: Advanced | Estimated Time: 4-7 hours

Assumption: Replacing both front struts and rear shocks.

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⚠️ Safety & Precautions

• ⚠️ Support the car with jack stands; never rely on a floor jack.
• ⚠️ Coil springs store serious energy—only use a spring compressor correctly; keep hands/face out of the spring’s path.
• ⚠️ Do not let the steering knuckle hang by brake hoses or ABS wiring; support it with a strap.
• ⚠️ If you loosen any suspension arms, tighten final torque at normal ride height to avoid bushing damage.
• ⚠️ An alignment is required after front strut replacement.

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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
• Torque wrench (20-200 Nm range)
• Breaker bar (1/2")
• 17mm socket
• 13mm socket
• 16mm socket
• 18mm socket
• 21mm socket
• E-Torx socket set (E10-E14)
• Torx bit set (T20-T30)
• Allen key set (6mm-8mm)
• Flat trim tool
• Pry bar
• Paint marker
• Spring compressor (specialty)
• Strut spreader bit (specialty)
• Bungee cord
• Penetrating oil

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Front strut assemblies - Replace in pairs - Qty: 2
• Front strut top mounts - Replace in pairs - Qty: 2
• Front strut mount bearing plates - Replace in pairs - Qty: 2
• Front bump stops and dust boots - Replace in pairs - Qty: 2
• Front pinch bolts/nuts (strut-to-knuckle) - Replace in pairs - Qty: 2
• Rear shock absorbers - Replace in pairs - Qty: 2
• Rear shock mounts - Replace in pairs - Qty: 2
• Rear bump stops and dust boots - Replace in pairs - Qty: 2
• Rear lower shock bolts/nuts - Replace in pairs - Qty: 2

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📋 Before You Begin

• Park on level ground, turn the wheel straight, and set the parking brake.
• Loosen lug bolts 1/2 turn with a 17mm socket before lifting.
• Lift the front and/or rear with a floor jack and support with jack stands at proper lift points.
• Spray penetrating oil on strut pinch bolts and sway bar link hardware and let it soak.
• Know this term: a knuckle is the big metal piece the wheel hub attaches to.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the front wheels

• Remove the lug bolts using a 17mm socket.
• Set wheels aside under the car as an extra safety backup.

Step 2: Free lines and sensors from the front strut

• Remove the brake hose/ABS wire brackets from the strut using a Torx T20-T30 bit or 10mm/13mm socket (varies by bracket).
• Use a flat trim tool to pop any plastic clips out of the strut.
• Tip: Don’t pull on the ABS wire.

Step 3: Disconnect the front sway bar link from the strut

• Remove the sway bar end link nut using a 16mm socket.
• If the stud spins, hold it with an Allen key (6mm) while turning the nut with the 16mm socket.
• Set the link aside.
• Torque to 65 Nm (48 ft-lbs) on reassembly.

Step 4: Loosen the strut-to-knuckle pinch bolt

• Support the knuckle with a bungee cord so it can’t drop.
• Remove the pinch bolt nut/bolt using an 18mm socket and breaker bar.
• Torque to 81 Nm (60 ft-lbs) on reassembly (use new hardware if supplied).

Step 5: Spread the knuckle clamp and separate the strut

• Insert a strut spreader bit (specialty) into the knuckle clamp slot and rotate slightly to open the clamp.
• Use a pry bar carefully to help the strut slide up and out of the knuckle.
• Tip: Mark the strut position with a paint marker.

Step 6: Remove the front strut top nuts

• Open the hood.
• At the top of the strut tower, remove the strut mount nuts using a 13mm socket (typically 3 nuts).
• Hold the strut so it doesn’t drop, then lift the strut assembly out.
• Torque to 34 Nm (25 ft-lbs) on reassembly.

Step 7: Swap the spring onto the new front strut (if not quick-struts)

• Install a spring compressor (specialty) on the coil spring and compress evenly until the spring is loose in the perch.
• Remove the top center nut using an E-Torx socket while counter-holding the shaft with an Allen key (typically 6mm-8mm).
• Transfer the spring, upper seat, bearing, dust boot, and bump stop to the new strut (replace worn items).
• Reinstall the top nut and tighten with a torque wrench.
• Torque to 64 Nm (47 ft-lbs) for the strut shaft top nut.
• Slowly release the spring compressor, making sure the spring ends seat correctly.
• Tip: Uneven compression is dangerous—go slowly.

Step 8: Reinstall the front strut assembly

• Guide the strut into the tower and start the top nuts by hand using a 13mm socket.
• Slide the strut fully into the knuckle (use your paint mark as a guide) and remove the spreader bit using the strut spreader bit (specialty).
• Install the new pinch bolt and tighten using an 18mm socket and torque wrench.
• Torque to 81 Nm (60 ft-lbs) for the pinch bolt.
• Tighten the top nuts using a 13mm socket.
• Torque to 34 Nm (25 ft-lbs) for the top mount nuts.

Step 9: Reattach sway link and brackets

• Reconnect the sway bar end link using a 16mm socket and counter-hold with a 6mm Allen key if needed.
• Torque to 65 Nm (48 ft-lbs).
• Reinstall brake hose/ABS brackets using a Torx bit or 10mm/13mm socket.
• Torque to 10 Nm (7 ft-lbs) for small bracket fasteners.

Step 10: Reinstall wheels (front)

• Install wheels and hand-thread all lug bolts.
• Lower the car, then torque lug bolts using a torque wrench.
• Torque to 140 Nm (103 ft-lbs).

Step 11: Rear shock replacement (rear “strut” service)

• Lift the rear and remove rear wheels using a 17mm socket.
• Support the rear lower control arm with a floor jack so the suspension doesn’t drop.
• Remove the lower shock bolt using an 18mm socket and breaker bar.
• Inside the trunk, remove side trim fasteners using a flat trim tool to access the upper shock mount nuts.
• Remove the upper mount nuts using a 13mm socket, then remove the shock.
• Transfer/replace mount, dust boot, and bump stop as needed, then install the new shock.
• Torque to 25 Nm (18 ft-lbs) for upper shock mount nuts.
• Torque to 100 Nm (74 ft-lbs) for the lower shock bolt.
• Reinstall wheels and torque lug bolts using a torque wrench.
• Torque to 140 Nm (103 ft-lbs).

Step 12: Final checks

• Double-check every fastener you touched using the torque wrench.
• Make sure brake hoses and ABS wires are clipped back in place and not twisted.

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✅ After Repair

• Start the car and turn the steering lock-to-lock slowly while parked; listen for clunks.
• Test drive at low speed first; re-check for noises over small bumps.
• Get a 4-wheel alignment as soon as possible (front struts affect camber/toe).
• Re-torque lug bolts after 25-50 miles using a torque wrench: 140 Nm (103 ft-lbs).

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💰 DIY vs Shop Cost

Shop Cost: $1,600-$3,200 (parts + labor, front + rear)

DIY Cost: $550-$1,600 (parts only, front + rear)

You Save: $1,050-$1,600 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 4-7 hours.

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🎯 Ready to get started?

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