Strut Mount - Front

Replace the front strut mounts on a 2007-2013 Mercedes-Benz S65 AMG, requiring strut removal and installation of new upper mount assemblies.

Warnings

Tools required

Parts

• Front strut mount assembly (left) × 1 — Use OEM specification
• Front strut mount assembly (right) × 1 — Use OEM specification
• Strut mount bearing (if not included) × 2 — Use OEM specification
• Upper strut nut × 2 — Use OEM specification
• Self-locking nuts (if applicable) × 1 — Replace all self-locking fasteners

Preparation

1. Park vehicle on level surface and engage parking brake. Chock rear wheels.
2. Verify vehicle has conventional coil spring suspension, not Airmatic air suspension system.
3. Loosen front wheel lug nuts while vehicle is on ground, but do not remove.
4. Raise front of vehicle using floor jack at designated front jacking point.
5. Support vehicle on jack stands positioned at proper lifting points on front subframe or rocker panels.
6. Remove front wheels completely.
7. Spray all suspension fasteners with penetrating oil and allow to soak for 15-20 minutes.
8. Take photos of strut orientation, sway bar link position, and ABS sensor routing for reference during reassembly.

Procedure

1. 1

   Access strut tower mounting area
   Open hood and locate the strut tower mounting nuts under the hood. On the S65 AMG, you may need to remove plastic engine covers or move aside insulation to access the three strut tower nuts. Do not remove nuts yet, only expose them for access.
2. 2

   Disconnect sway bar link from strut
   Locate the sway bar link connection to the strut assembly. Use an Allen key to hold the internal shaft of the link while loosening the top nut with a socket. Remove the nut completely and separate the sway bar link from the strut. Allow the link to hang from the sway bar.
   Torque spec

   Sway Bar Link82 Nm (61 lb-ft)
3. 3

   Disconnect ABS sensor and brake line
   Locate the ABS wheel speed sensor wire attached to the strut with clips or brackets. Carefully remove clips and separate sensor wire from strut without damaging the wire. If brake line is secured to strut with brackets, remove bracket bolts to allow strut removal clearance. Do not disconnect hydraulic brake lines.
4. 4

   Remove strut-to-knuckle bolts
   Locate the two large bolts connecting the bottom of the strut to the steering knuckle. These are typically pinch-type bolts with alignment tabs. Use a breaker bar to loosen these bolts, then remove completely. You may need to use a pry bar to spread the knuckle clamp slightly to free the strut. Note the alignment position of any eccentric washers or cam bolts for initial reassembly reference.
   ⚠Support the strut from below as you remove the knuckle bolts, as it will become loose once bolts are removed.
   Torque spec

   Strut-to-Knuckle Bolts165 Nm (122 lb-ft)
5. 5

   Remove strut tower mounting nuts
   Return to the engine bay and locate the three nuts securing the strut mount to the strut tower. Have an assistant support the strut from below, or use a jack with a block of wood to support the strut. Remove all three nuts at the top of the strut tower. Carefully lower and remove the entire strut assembly from the vehicle through the wheel well.
   ⚠The strut assembly is heavy and awkward. Ensure it is properly supported before removing the last mounting nut.
   Torque spec

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

   Mount strut in vice and install spring compressors
   Secure the strut assembly in a strut vice or holding fixture with soft jaws to avoid damaging the strut body. Install spring compressors on opposite sides of the coil spring (180 degrees apart). Tighten compressors evenly and gradually, alternating between sides every few turns, until the spring is compressed enough that the upper mount has no load. The spring should compress approximately 2-3 inches.
   ⚠️Ensure spring compressors are properly engaged on the coils and tightened evenly. Uneven compression or improperly seated compressors can cause violent spring release.
7. 7

   Remove strut shaft nut and old mount
   Once spring is fully compressed and upper mount is unloaded, use a socket on the top nut while holding the strut shaft with an Allen key or holding tool inserted from the top. Remove the shaft nut completely. Carefully remove the upper mount assembly, bearing plate, and spring seat. Note the orientation and order of all components for reassembly. Remove spring compressors from spring.
   ⚠Even with compressors installed, maintain control of all components as you disassemble. Keep hands clear of spring path.
8. 8

   Inspect components and prepare for reassembly
   Inspect the strut shaft for damage, scoring, or leaking seals. Check the spring for cracks or damage. Clean the strut shaft threads with a wire brush. Compare new strut mount to old mount to verify correct part. Check that new mount includes bearing assembly or install new bearing if separate.
9. 9

   Reassemble strut with new mount
   Install spring compressors on the spring and compress as before. Place spring on strut body in correct orientation. Install lower spring seat if equipped, then the compressed spring, upper spring seat, bearing assembly, and new strut mount in correct order. Ensure all components are properly aligned with any locating tabs or notches. Install new shaft nut and tighten to specification while holding shaft from rotating. Gradually and evenly release spring compressors, verifying proper seating of all components.
   ⚠️As you release spring compressors, verify that spring seats properly and evenly on both upper and lower perches. If binding occurs, stop immediately and re-compress spring.
   Torque spec

   Strut Tower Nuts50 Nm (37 lb-ft)
10. 10

    Install strut assembly into vehicle
    Lift the assembled strut into position through the wheel well. Align the upper mount studs with holes in the strut tower. Install the three strut tower nuts and tighten to specification. Ensure the mount is properly seated against the tower before final torquing.
    Torque spec

    Strut Tower Nuts50 Nm (37 lb-ft)
11. 11

    Connect strut to steering knuckle
    Align the bottom of the strut with the steering knuckle clamp. If the fit is tight, use a pry bar to carefully spread the knuckle clamp. Insert the strut fully into the knuckle, ensuring any alignment tabs are properly positioned. Install both strut-to-knuckle bolts and tighten to specification. Verify that any eccentric washers or cam bolts are in approximately the same position as noted during disassembly.
    Torque spec

    Strut-to-Knuckle Bolts165 Nm (122 lb-ft)
12. 12

    Reconnect sway bar link and sensors
    Raise the sway bar link to the strut mounting point. Install the link nut while holding the internal shaft with an Allen key to prevent rotation. Tighten to specification. Reattach ABS sensor wire to clips or brackets on strut. Reinstall any brake line brackets that were removed.
    Torque spec

    Sway Bar Link82 Nm (61 lb-ft)
13. 13

    Repeat for opposite side
    Perform all steps (2 through 12) on the opposite side front strut to replace the second strut mount. Always replace strut mounts in pairs to maintain balanced suspension characteristics.
14. 14

    Install wheels and lower vehicle
    Install front wheels and hand-tighten lug nuts in a star pattern. Lower vehicle until wheels just touch ground but vehicle weight is not fully on suspension. Torque wheel lug nuts to specification in a star pattern. Fully lower vehicle and remove jack stands.
    Torque spec

    Wheel Lug Nuts183 Nm (135 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to specification, particularly the safety-critical strut tower nuts, strut-to-knuckle bolts, and wheel lug nuts.
2. Verify that ABS sensor wires are properly routed and secured away from moving suspension components and heat sources.
3. Check that brake lines have adequate clearance and are not stretched or kinked.
4. Reinstall any engine covers or insulation that were removed for strut tower access.

Verification

• Before driving, bounce each front corner of the vehicle several times and verify no unusual noises, binding, or looseness from strut area.
• Perform a careful test drive at low speed in a safe area, checking for proper steering response, unusual noises, and vibrations.
• Verify no clunking or rattling noises over bumps that would indicate loose strut mount installation.
• Schedule a professional four-wheel alignment immediately, as strut removal and installation affects camber, caster, and toe settings. Do not delay alignment as this affects tire wear and vehicle handling.
• After 50-100 miles of driving, re-torque all suspension fasteners to specification and re-inspect for any looseness or unusual wear patterns.

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