suspension
Radius Arm Bushing
for 2012 Mercedes-Benz S65 AMG 6.0L V12 BiTurbo M275 · RWD
Difficulty
Advanced
Time
3.4 h
Tools
10
Steps
14
✓Fact-checked. Built from OLP's spec database, then independently fact-checked line by line with every correction applied. Master-tech sign-off by Chris Hackleman is queued. Cross-check torque values against the factory manual, and stop if anything looks unsafe. How our data is made.
Replace the radius arm bushings on the rear suspension to restore proper alignment geometry and eliminate clunking noises during acceleration and braking.
Warnings
⚠️Vehicle must be properly supported on jack stands at all times. Never work under a vehicle supported only by a hydraulic jack.
⚠Suspension components are under load even when vehicle is raised. Use caution when removing bolts and support components before fully releasing.
⚠Control arm bolts must be torqued with vehicle weight on wheels or damage to bushings will occur.
ℹ️Alignment is required after this procedure. Schedule alignment before driving extensively.
Tools required
Torque wrench (30-200 Nm range)Essential
19mm socket and wrenchEssential
21mm socket and wrenchEssential
Hydraulic press or bushing press kitEssential
Ball joint separator toolEssential
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Parts
- Radius arm bushing (front) × 2 — Use OEM specification A2213333014
- Radius arm bushing (rear) × 2 — Use OEM specification A2213333114
- Ball joint nut (if damaged) × 2 — Use OEM specification
- Mounting hardware (if corroded) × 1 — Use OEM specification
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Preparation
- Park vehicle on level surface and engage parking brake
- Loosen rear wheel lug nuts while vehicle is on ground
- Raise vehicle on lift or use jack stands at proper jacking points under chassis
- Remove rear wheels completely
- Spray all suspension bolts with penetrating oil and allow to soak for 15-20 minutes
- Mark orientation of radius arm to subframe for reference during installation
Procedure
- 1Disconnect radius arm ball jointLocate the ball joint connecting the radius arm to the rear hub carrier. Remove the ball joint nut using a 21mm socket. Use a ball joint separator tool to disconnect the ball joint from the hub carrier. Do not hammer on suspension components as this can damage the aluminum carrier.Torque specBall Joint Nut119 Nm (88 lb-ft)
- 2Remove rear radius arm mounting boltLocate the rear mounting bolt that connects the radius arm to the subframe. This is the larger mounting point at the rear of the arm. Use a 21mm socket and wrench to remove the bolt completely. Support the radius arm with one hand as you remove the final threads, as the arm may drop suddenly.⚠The radius arm will pivot downward once this bolt is removed. Keep hands clear of pinch points.Torque specControl Arm Bolts165 Nm (122 lb-ft)
- 3Remove front radius arm mounting boltLocate the front mounting bolt that connects the radius arm to the subframe bracket. This is typically closer to the center of the vehicle. Use a 19mm socket and wrench to remove the bolt while supporting the radius arm. Once removed, lower the radius arm and remove it from the vehicle.Torque specControl Arm Bolts165 Nm (122 lb-ft)
- 4Inspect radius arm and prepare for bushing removalPlace the radius arm on a workbench. Inspect the arm for cracks, bends, or damage. Clean the bushing mounting areas with a wire brush. Mark the orientation of the existing bushings before removal if they are not completely deteriorated. Note that front and rear bushings are different and cannot be interchanged.ℹ️Front and rear bushings have different part numbers and orientations. Keep them separated during the procedure.
- 5Press out old bushingsUsing a hydraulic press or bushing press kit, carefully press out the old bushings from both mounting locations on the radius arm. The bushings are press-fit and may require significant force. Use the proper size adapters to avoid damaging the radius arm housing. Ensure the arm is properly supported during pressing to prevent bending.⚠Ensure the radius arm is properly supported and aligned in the press to prevent distortion of the mounting eyes.
- 6Clean bushing boresOnce old bushings are removed, thoroughly clean the bushing bores in the radius arm using a wire brush and solvent. Remove all rubber residue, corrosion, and debris. The bores must be completely clean for proper new bushing installation. Inspect the bores for damage or out-of-round condition.
- 7Press in new bushingsApply a light coat of soapy water or bushing lubricant to the outer sleeve of the new bushings. Position the correct bushing (front or rear) in the appropriate mounting eye, ensuring proper orientation. Use the hydraulic press with proper adapters to press the new bushing straight into the bore until fully seated and flush with the arm. The bushing inner sleeve should be perpendicular to the arm. Repeat for both mounting locations.⚠Bushings must be pressed in straight to avoid binding or premature failure. Do not use grease as it can cause the bushing to slip out over time.
- 8Install radius arm to subframe (front bolt first)Position the radius arm back into the vehicle, aligning the front mounting eye with the subframe bracket. Insert the front mounting bolt but only hand-tighten at this stage. The bolt should pass through the bushing inner sleeve easily. Do not fully torque yet.
- 9Install rear mounting boltAlign the rear mounting eye with the subframe mounting point. You may need to use a pry bar to align the holes. Insert the rear mounting bolt and hand-tighten. Ensure both bolts are properly started before proceeding. Do not torque these bolts yet as they must be torqued with vehicle weight on suspension.
- 10Reconnect ball joint to hub carrierLift the radius arm ball joint into position in the hub carrier. Install the ball joint nut and torque to specification using a 21mm socket and torque wrench. Ensure the ball joint stud is fully seated in the taper before torquing.Torque specBall Joint Nut119 Nm (88 lb-ft)
- 11Repeat procedure for opposite sidePerform steps 1 through 10 on the opposite rear radius arm to replace both sides. Both radius arms should be replaced as a pair to maintain balanced suspension geometry and handling characteristics.
- 12Install wheels and lower vehicleReinstall both rear wheels and hand-tighten the lug nuts in a star pattern. Lower the vehicle until the suspension is at normal ride height with full vehicle weight on the wheels, but keep the vehicle raised slightly so wheels can still rotate. This simulates loaded suspension condition.Torque specWheel Lug Nuts183 Nm (135 lb-ft)
- 13Torque radius arm mounting bolts with vehicle weight on suspensionWith the vehicle at normal ride height, torque both the front and rear radius arm mounting bolts on both sides to specification. This must be done with the suspension loaded to prevent pre-loading the bushings, which would cause premature failure. Use a 19mm or 21mm socket and torque wrench as appropriate for each bolt location.⚠Failure to torque with vehicle weight on suspension will cause bushing failure within a few thousand miles.Torque specControl Arm Bolts165 Nm (122 lb-ft)
- 14Final torque wheel lug nutsFully lower the vehicle to the ground. Final torque all wheel lug nuts to specification in a star pattern using a torque wrench.Torque specWheel Lug Nuts183 Nm (135 lb-ft)
Reassembly
- Verify all mounting bolts are torqued to specification with vehicle at ride height
- Verify ball joints are fully seated and torqued on both sides
- Check that no tools or parts were left in the suspension area
- Test drive vehicle at low speed in a safe area to verify no abnormal noises or handling issues before scheduling alignment
Verification
- Bounce each rear corner of the vehicle and listen for any clunking or abnormal noises from the radius arm area
- Verify the vehicle tracks straight during gentle acceleration and braking at low speed
- Schedule four-wheel alignment immediately, as radius arm bushing replacement affects rear toe and camber settings
- After alignment, verify tire wear patterns return to normal over the next 1000 miles