Coil Spring - Front

This procedure covers the removal and replacement of front coil springs on the 2007-2013 Mercedes-Benz S65 AMG, requiring disassembly of the front strut assembly and use of a spring compressor.

Warnings

Tools required

Parts

• Front coil spring (left and/or right) × 2 — Use OEM specification
• Strut mount bearing (recommended) × 2 — Use OEM specification
• Strut bump stop (recommended) × 2 — Use OEM specification
• Upper strut mount nuts (if corroded) × 6 — Use OEM specification

Preparation

1. Park vehicle on level, solid surface and engage parking brake.
2. Loosen front wheel lug nuts while vehicle is on ground (do not remove).
3. Lift front of vehicle using floor jack at manufacturer-specified jacking points and support securely on jack stands under subframe.
4. Remove both front wheels completely.
5. Spray all suspension fasteners with penetrating oil and allow 15-20 minutes to soak if vehicle has rust or corrosion.
6. Take photos of the suspension assembly from multiple angles for reference during reassembly.
7. If vehicle is equipped with Active Body Control (ABC) suspension, verify this procedure matches your suspension type. ABC-equipped vehicles require different procedures.

Procedure

1. 1

   Disconnect sway bar end link
   Locate the front sway bar end link connecting the sway bar to the strut assembly. Hold the internal shaft with an Allen key to prevent spinning, then remove the upper nut securing the link to the strut. If the link is worn or the boot is torn, replace it during reassembly.
   Torque spec

   Sway Bar Link Nuts55 Nm (41 lb-ft)
2. 2

   Disconnect ABS wheel speed sensor
   Locate the ABS wheel speed sensor wire attached to the strut or control arm. Carefully disconnect the electrical connector and unbolt any mounting clips securing the wire to the strut. Route the wire safely away from the work area to prevent damage.
   ⚠Do not pull on the ABS sensor wire. These sensors are fragile and expensive to replace.
3. 3

   Remove strut-to-knuckle bolts
   Locate the two large bolts connecting the bottom of the strut to the steering knuckle. These are pinch bolts that clamp the knuckle to the strut. Support the knuckle assembly with a jack or secure it with wire to prevent it from dropping. Remove both bolts completely. You may need to spread the knuckle slightly with a pry bar to separate it from the strut.
   ⚠The knuckle assembly is heavy and will drop when separated from the strut. Support it with a jack or tie it up with wire to prevent damage to brake lines and CV joints.
   Torque spec

   Strut Bolts156 Nm (115 lb-ft)
4. 4

   Access strut tower mounting nuts
   Open the hood and locate the strut tower in the engine compartment. Remove any plastic covers or trim panels covering the upper strut mount. You will see three nuts securing the strut mount to the strut tower.
   ℹ️On the S65 AMG, engine components may restrict access to the strut tower. Work carefully around turbocharger heat shields and intake components.
5. 5

   Remove strut assembly
   Support the strut assembly from below with one hand or have an assistant hold it. Remove all three upper strut tower nuts. Carefully lower the strut assembly down and out through the wheel well. The assembly is heavy and awkward to maneuver.
   ⚠The strut assembly weighs approximately 35-45 lbs and contains a compressed spring. Handle with care and do not allow it to drop.
   Torque spec

   Strut Tower Nuts50 Nm (37 lb-ft)
6. 6

   Secure strut in vice
   Mount the strut assembly in a heavy-duty bench vice or strut vice, clamping on the lower strut body (not the shaft or spring). Position the assembly so the spring is vertical and accessible from all sides. Ensure the vice holds the strut securely.
   ⚠️The strut must be held absolutely securely before compressing the spring. A strut that shifts or falls during spring compression can cause catastrophic injury.
7. 7

   Install spring compressor
   Install a coil spring compressor according to the manufacturer's instructions. Use compression tools that hook through the coils, ensuring they are positioned 180 degrees apart for balanced compression. Verify that the compressor hooks are fully engaged with the spring coils and cannot slip. Begin compressing the spring gradually, alternating between the two sides of the compressor to maintain even compression.
   ⚠️Compress the spring slowly and evenly. Check frequently that the compressor hooks remain fully engaged. Never stand directly over the spring during compression.
   ⚠️The spring must be compressed enough that all tension is removed from the upper strut mount. Test by attempting to rotate the mount - it should turn freely.
8. 8

   Remove strut shaft nut
   Once the spring is fully compressed and tension is released from the upper mount, hold the strut shaft with a wrench or Allen key to prevent rotation. Remove the large nut securing the upper strut mount to the shaft. Carefully remove the upper mount, bearing plate, and upper spring seat. Keep all components in order for reassembly.
   ⚠If the spring is not fully compressed, the upper mount will be under tension and removing the nut will be dangerous. Verify zero tension before removing the nut.
9. 9

   Remove old spring and inspect components
   With the compressor still engaged, carefully remove the compressed spring from the strut. Remove the bump stop and dust boot from the strut shaft. Inspect the strut for leaks - any oil leakage indicates the strut should be replaced. Inspect the upper mount bearing for wear, roughness, or binding. Replace if defective. Inspect all rubber components for cracking or deterioration.
   ⚠Keep the spring compressor engaged on the old spring until you are ready to dispose of it or reinstall it. Never release a compressed spring in an uncontrolled manner.
10. 10

    Install new spring
    Install the new coil spring onto the spring compressor and compress it to the same degree as the old spring was compressed. The spring must be compressed enough to install without force. Position the lower end of the spring correctly in the lower spring seat on the strut body - there is usually a tab or stop that the spring end must align with. Verify correct orientation before proceeding.
    ⚠The spring end must seat properly in the lower spring perch. Incorrect installation can cause spring failure and loss of vehicle control.
11. 11

    Reassemble strut components
    Install new or inspected bump stop and dust boot onto the strut shaft. Slide the compressed spring over the strut body. Install the upper spring seat, ensuring the top of the spring seats correctly against any tabs or stops. Install the bearing plate with the correct orientation (bearing should rotate smoothly). Install the upper strut mount, aligning any positioning marks or tabs. Thread the shaft nut onto the strut shaft finger-tight.
    ℹ️The upper spring seat and strut mount often have specific rotational alignment. Refer to your reference photos or marks made during disassembly.
12. 12

    Torque shaft nut and release spring
    Hold the strut shaft to prevent rotation and torque the upper shaft nut to manufacturer specification (typically 50-60 Nm, but verify with specific Mercedes documentation). Slowly and evenly release the spring compressor, alternating sides to decompress evenly. As the spring decompresses, verify it seats correctly in both upper and lower spring seats. Once fully released, remove the compressor tools.
    ⚠️Release the spring compressor very slowly and watch for any signs of misalignment or improper seating. If anything appears wrong, stop immediately and recompress the spring to correct the issue.
13. 13

    Install strut assembly into vehicle
    Maneuver the completed strut assembly up into the wheel well. Align the upper mount studs with the holes in the strut tower. Install all three upper mounting nuts and tighten to specification. Guide the bottom of the strut into position with the steering knuckle.
    Torque spec

    Strut Tower Nuts50 Nm (37 lb-ft)
14. 14

    Connect strut to knuckle
    Align the steering knuckle with the strut. You may need to use a pry bar to spread the knuckle pinch clamp slightly. Push the knuckle fully onto the strut until it seats completely. Install both strut-to-knuckle bolts and tighten to specification. Ensure the knuckle is fully seated before final torquing.
    ⚠The strut must be fully inserted into the knuckle pinch clamp before torquing. Incomplete seating will affect alignment and handling.
    Torque spec

    Strut Bolts156 Nm (115 lb-ft)
15. 15

    Reconnect components and install wheel
    Reconnect the ABS wheel speed sensor connector and secure the wire with all mounting clips. Reconnect the sway bar end link to the strut, holding the internal shaft with an Allen key and torquing the nut to specification. Install the wheel and hand-tighten the lug nuts in a star pattern. Lower the vehicle until the tire just touches the ground (weight still on jack stands) and torque the lug nuts to specification in a star pattern.
    Torque spec

    Sway Bar Link Nuts55 Nm (41 lb-ft)

    Wheel Lug Nuts183 Nm (135 lb-ft)

Reassembly

1. Repeat all steps for the opposite side if replacing both springs.
2. Reinstall any plastic covers or trim panels removed from the strut towers.
3. Remove jack stands and fully lower the vehicle to the ground.
4. With the vehicle weight fully on the wheels, bounce each corner of the vehicle several times to settle the suspension.
5. Re-check all fastener torques, particularly wheel lug nuts, after the suspension has settled.
6. Test drive the vehicle in a safe area at low speeds before returning to normal operation.

Verification

• Verify the vehicle sits at the correct ride height on level ground. Uneven height indicates improper spring installation or suspension damage.
• Verify no abnormal noises from the front suspension when driving over bumps or turning.
• Check that steering returns to center normally and there is no binding in the steering system.
• Verify ABS warning light is not illuminated on the dashboard (indicates sensor reconnection was successful).
• Have a four-wheel alignment performed immediately. Verify alignment specifications are within Mercedes-Benz factory tolerances.
• After 50-100 miles of driving, re-torque all suspension fasteners and wheel lug nuts to specification.
• Inspect for any signs of spring noise, suspension settling, or abnormal tire wear after 500 miles.

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle