🔧 GLC300 - Shock Absorber/Strut Replacement

On your GLC300, the front uses a strut (shock built into a spring/strut assembly) and the rear uses a separate shock. Replacing worn shocks/struts restores ride control, braking stability, and tire wear.

Difficulty Level: Advanced | Estimated Time: 6-10 hours

Assumption: steel-spring suspension (not AIRMATIC). Steps include both front and rear.

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⚠️ Safety & Precautions

• ⚠️ Support the vehicle with jack stands; never rely on a jack.
• ⚠️ Front struts are under spring tension—use a quality spring compressor correctly.
• ⚠️ Do not let the steering knuckle hang by the brake hose or ABS wire.
• ⚠️ If equipped with AIRMATIC/air suspension, do not proceed—air system must be depressurized and put in safe mode first.
• ⚠️ Keep hands clear of pinch points when lowering/raising the control arm.

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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 1/2"
• Torque wrench 20–200 Nm (15–150 ft-lbs)
• Socket set 8mm–24mm (1/2" drive)
• Wrench set 8mm–24mm
• E-Torx socket set E10–E18
• Torx bit set T20–T50
• Pry bar 18"
• Rubber mallet
• Needle-nose pliers
• Trim clip removal tool
• Paint marker
• Penetrating oil
• Spring compressor (external, threaded-rod type) (specialty)
• Strut spreader tool (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Front struts (left and right) - Qty: 2
• Front strut mount and bearing kit - Qty: 2
• Front bump stop and dust boot kit - Qty: 2
• Rear shock absorbers (left and right) - Qty: 2
• Rear bump stop and dust boot kit - Qty: 2
• New self-locking nuts/bolts for strut-to-knuckle, sway link, and shock mounts - Qty: 1 kit
• Anti-seize compound - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Loosen the wheel lug bolts slightly before lifting (do not remove yet).
• Spray penetrating oil on the lower strut pinch area, sway-bar link nuts, and rear shock bolts.
• Plan on getting a 4-wheel alignment after front strut replacement.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Lift and remove the wheels

• Use a floor jack (rated 3-ton minimum) to lift at the approved jacking point.
• Set the vehicle securely on jack stands (rated 3-ton minimum).
• Remove lug bolts using a 17mm socket (size may vary by wheel) and take off the wheels.

Step 2: Front strut removal (one side at a time)

• Turn the steering to give yourself space at the strut/knuckle area.
• Unclip any brake hose/ABS wire brackets from the strut using needle-nose pliers and a trim clip removal tool.
• Remove the sway-bar end link from the strut using the correct socket set 8mm–24mm and Torx bit set T20–T50 to counter-hold the stud.
• Support the steering knuckle with a floor jack (rated 3-ton minimum) so it can’t drop.
• Remove the strut-to-knuckle pinch bolt using E-Torx socket set E10–E18 and a breaker bar 1/2".
• Insert the strut spreader tool (specialty) into the knuckle slot to slightly open the clamp. Only spread enough to release.
• Under the hood, remove the strut mount nuts using a socket set 8mm–24mm.
• Work the strut out of the knuckle and remove it from the wheel well.

Step 3: Swap the spring onto the new front strut

• Install the spring compressor (external, threaded-rod type) (specialty) on opposite sides of the spring.
• Tighten evenly with a wrench set 8mm–24mm until the spring is loose in the mount. Compress slowly and evenly.
• Mark the spring orientation with a paint marker so it goes back the same way.
• Remove the top nut using a socket set 8mm–24mm and counter-hold with the appropriate Torx bit set T20–T50 if required.
• Transfer/install new strut mount and bearing kit and bump stop and dust boot kit.
• Reinstall the top nut and Torque to Mercedes-Benz spec (WIS) for the front strut piston rod nut.
• Slowly release the spring compressor, ensuring the spring seats properly in the lower perch and upper mount.

Step 4: Reinstall the front strut

• Position the strut in the tower and hand-start the top mount nuts using a socket set 8mm–24mm.
• Guide the strut into the knuckle. Use a floor jack (rated 3-ton minimum) to raise/lower the knuckle for alignment.
• Install a new pinch bolt and nut using E-Torx socket set E10–E18, then Torque to Mercedes-Benz spec (WIS) for strut-to-knuckle pinch bolt.
• Reattach the sway-bar end link using the proper socket set 8mm–24mm and Torx bit set T20–T50, then Torque to Mercedes-Benz spec (WIS) for sway-bar end link fastener.
• Reinstall all brake hose/ABS wire brackets and clips using needle-nose pliers.
• Tighten the top mount nuts using a torque wrench 20–200 Nm (15–150 ft-lbs) and Torque to Mercedes-Benz spec (WIS) for strut mount nuts.

Step 5: Rear shock removal (one side at a time)

• Support the rear lower control arm with a floor jack (rated 3-ton minimum).
• Remove the lower shock bolt using the appropriate socket set 8mm–24mm and breaker bar 1/2".
• Access the upper rear shock mount fasteners (typically behind trunk/cargo side trim).
• Remove the necessary trim carefully using a trim clip removal tool and Torx bit set T20–T50.
• Remove the upper shock mount nuts/bolt using a socket set 8mm–24mm, then remove the shock.

Step 6: Reinstall the rear shock

• Install the new rear shock with new rear bump stop and dust boot kit.
• Hand-start the upper fasteners using a socket set 8mm–24mm.
• Align the lower mount by raising/lowering the control arm with a floor jack (rated 3-ton minimum).
• Install the lower bolt using a socket set 8mm–24mm, then Torque to Mercedes-Benz spec (WIS) for rear shock lower bolt.
• Tighten the upper mount fasteners using a torque wrench 20–200 Nm (15–150 ft-lbs), then Torque to Mercedes-Benz spec (WIS) for rear shock upper mount.
• Reinstall the cargo trim using a Torx bit set T20–T50 and trim clip removal tool.

Step 7: Reinstall wheels and set the vehicle down

• Put the wheels back on and hand-thread the lug bolts.
• Lower the vehicle off the jack stands (rated 3-ton minimum) using the floor jack (rated 3-ton minimum).
• Tighten lug bolts in a star pattern with a torque wrench 20–200 Nm (15–150 ft-lbs) and Torque to Mercedes-Benz spec (WIS) for wheel lug bolts.

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✅ After Repair

• Test drive slowly at first and listen for clunks over small bumps.
• Recheck that all brake hose/ABS wire clips are secured and not rubbing.
• Get a 4-wheel alignment as soon as possible (front struts affect camber/toe).
• After 50–100 miles, recheck for any loose fasteners or new noises.

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💰 DIY vs Shop Cost

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

DIY Cost: $450-$1,400 (parts only)

You Save: $1,150-$1,800 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 5-8 hours.

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🎯 Ready to get started?

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