Trailing Arm Bushing

Replace the rear trailing arm bushings on a 2007-2013 Mercedes-Benz S65 AMG to restore suspension geometry and eliminate clunking or excessive rear axle movement.

Warnings

Tools required

Parts

• Rear trailing arm bushing (inner) × 2 — A221 350 03 06 or equivalent
• Rear trailing arm bushing (outer) × 2 — A221 350 04 06 or equivalent
• Control arm mounting bolts × 4 — Use OEM specification (replace if corroded)

Preparation

1. Park vehicle on level surface and engage parking brake.
2. If equipped with AIRMATIC suspension, use instrument cluster menu to select 'Raise Vehicle' mode or manually deflate rear air springs using Star Diagnostic tool to prevent overextension.
3. Loosen rear wheel lug nuts while vehicle is on ground (do not remove).
4. Raise rear of vehicle using floor jack at designated rear subframe jacking points.
5. Support vehicle on jack stands at reinforced rocker panel jacking points, ensuring adequate working clearance under vehicle.
6. Remove both rear wheels completely.
7. Spray all trailing arm mounting bolts, control arm bolts, and ball joint nuts with penetrating oil and allow 15-20 minutes to soak.

Procedure

1. 1

   Disconnect rear stabilizer link
   Locate the rear sway bar link connected to the trailing arm. Insert an Allen key into the ball stud shaft to prevent rotation. Using an 18mm wrench, remove the lower stabilizer link nut from the trailing arm mount. Note: Only disconnect lower end; upper connection to sway bar can remain attached.
   Torque spec

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

   Support rear hub assembly
   Position a floor jack with a wood block under the rear hub carrier assembly to support its weight. Raise jack just enough to take load off suspension components but do not lift the chassis. This prevents the assembly from dropping when control arm is disconnected.
3. 3

   Mark alignment reference points
   Using a paint pen or punch, mark the position of the trailing arm relative to the subframe mounting bracket and the hub carrier. These reference marks will assist with approximate realignment during reassembly, though professional alignment is still required.
4. 4

   Remove trailing arm-to-hub carrier bolt
   Locate the rear ball joint or control arm connection where the trailing arm connects to the hub carrier (rear knuckle). Remove the 18mm ball joint nut. If ball joint taper is seized, use a ball joint separator or pickle fork to break the taper connection. Remove the bolt completely and note any shims or washers present.
   Torque spec

   Ball Joint Nut119 Nm (88 lb-ft)
5. 5

   Remove trailing arm front mounting bolts
   Locate the two control arm bolts at the front of the trailing arm where it mounts to the rear subframe. These are the primary bushings being replaced. Using a breaker bar and 18mm socket, remove both mounting bolts while supporting the trailing arm. The arm may be under slight tension, so control its movement as bolts are extracted.
   ⚠Trailing arm may shift position suddenly when bolts are removed. Keep hands clear of pinch points between arm and subframe.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
6. 6

   Remove trailing arm from vehicle
   With all mounting points disconnected, carefully maneuver the trailing arm out of the subframe mounting bracket and away from the hub carrier. The arm is heavy (approximately 40-60 lbs); use proper lifting technique. Place on a clean workbench for bushing removal.
7. 7

   Remove old bushings from trailing arm
   Inspect the old bushings in the trailing arm eyes. If bushings are severely deteriorated, cut through the outer metal sleeve using a reciprocating saw or hacksaw (cut only the bushing sleeve, not the arm itself). Use a hydraulic press with appropriately sized adapters to press out the old bushing from the arm bore. If no press is available, a specialized trailing arm bushing removal tool can be used. Clean the bushing bore thoroughly with a wire brush and inspect for cracks or damage.
   ⚠When cutting or pressing bushings, ensure the trailing arm is properly supported to prevent deformation of the mounting eyes.
8. 8

   Press new bushings into trailing arm
   Apply a thin film of soapy water or bushing installation lubricant to the outer sleeve of the new bushings (do not use petroleum-based products that can degrade rubber). Position the new bushing squarely in the arm bore, ensuring any orientation markings or voids align with Mercedes specifications (typically voids face vertically). Use a hydraulic press with proper adapters to press the bushing straight into the bore until fully seated and flush with the arm mounting eye. Repeat for second bushing if arm has two mounting points.
   ⚠Bushings must be pressed in perfectly straight. Cocked bushings will bind and cause premature failure. Verify alignment before applying full press force.
9. 9

   Reinstall trailing arm to subframe
   Lift the trailing arm back into position, aligning the bushing eyes with the subframe mounting brackets using your alignment reference marks as a guide. Insert the control arm bolts through the subframe brackets and new bushings, threading them in by hand. Do NOT torque these bolts yet—they must be tightened with vehicle weight on wheels. Thread bolts in just enough to hold the arm securely in position.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
10. 10

    Reconnect trailing arm to hub carrier
    Raise or lower the floor jack supporting the hub carrier to align the trailing arm ball joint or mounting point with the hub carrier bracket. Insert the mounting bolt and reinstall any shims in their original positions. Thread on the ball joint nut and torque to specification using an 18mm socket and torque wrench.
    Torque spec

    Ball Joint Nut119 Nm (88 lb-ft)
11. 11

    Reconnect stabilizer link
    Align the stabilizer link lower ball stud with the mounting point on the trailing arm. Thread on the nut, insert an Allen key to hold the ball stud shaft from rotating, and torque the nut to specification.
    Torque spec

    Sway Bar Link Nuts55 Nm (41 lb-ft)
12. 12

    Reinstall wheels and lower vehicle to settle suspension
    Install both rear wheels and hand-tighten lug nuts in a star pattern. Remove jack stands and carefully lower the vehicle until the full weight is resting on the suspension (wheels on ground). This loads the suspension and settles the new bushings into their operating position.
13. 13

    Final torque control arm bolts with weight on wheels
    With the vehicle's full weight on the wheels, crawl under the vehicle and torque both trailing arm front control arm bolts to final specification. This is critical—torquing these bolts with the suspension hanging will preload the bushings incorrectly and cause premature failure and binding. After torquing, torque the wheel lug nuts to specification in a star pattern.
    ⚠️Vehicle must be supported on jack stands in addition to wheels on ground for safety while working underneath to torque bolts.
    ⚠Control arm bolt torque is only valid when performed with vehicle weight on suspension. Torquing with suspension unloaded will destroy the new bushings.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)

    Wheel Lug Nuts183 Nm (135 lb-ft)
14. 14

    Reactivate air suspension if equipped
    If vehicle has AIRMATIC suspension that was deflated or disabled, clear any fault codes using Star Diagnostic tool and allow the system to self-level. Check for any suspension warning lights on the instrument cluster.

Reassembly

1. Repeat entire procedure for opposite side trailing arm if both sides require replacement.
2. Test drive vehicle at low speed in a safe area and listen for any clunking or unusual noises from the rear suspension before returning to normal service.

Verification

• Visually inspect all mounting bolts to confirm proper torque and no visible gaps between components.
• Check that rear of vehicle sits at proper ride height with no sagging or uneven stance.
• Road test vehicle and verify no clunking noises from rear suspension over bumps or during acceleration/braking.
• Schedule four-wheel alignment immediately—confirm rear camber, toe, and thrust angle are within Mercedes-Benz specification (typically ±0.5° for camber, ±0.10° for toe).
• After 50-100 miles of driving, re-check control arm bolt torque to ensure no loosening has occurred.

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