Leaf Spring Bushing

Replace worn or damaged leaf spring bushings on the rear air suspension, restoring proper rear suspension alignment and ride quality.

Warnings

Tools required

Parts

• Rear leaf spring bushing kit × 2 — Use OEM specification
• Control arm mounting hardware (if corroded) × 1 — Use OEM specification

Preparation

1. Connect Mercedes-Benz Star Diagnostic (SDS) to vehicle and enter Service Mode for air suspension
2. Using SDS, deactivate the AIRMATIC system and vent all air springs to fully deflate them
3. Park vehicle on level surface and apply parking brake
4. Chock front wheels securely
5. Loosen rear wheel lug nuts while vehicle is on ground
6. Raise rear of vehicle and support on jack stands at factory lift points on frame rails
7. Remove both rear wheels
8. Spray all suspension fasteners with penetrating oil and allow to soak

Procedure

1. 1

   Remove rear wheel and access suspension
   With vehicle supported on jack stands and air suspension fully deflated, remove the rear wheel on the side being serviced. Inspect the leaf spring (lower trailing arm) and locate the front and rear bushing mounting points. The front bushing connects to the rear subframe, while the rear bushing connects to the wheel carrier assembly.
2. 2

   Disconnect air spring and ride height sensor
   Disconnect the electrical connector from the air spring. Remove the air line connection at the top of the air spring using the appropriate release tool. Disconnect the ride height sensor linkage from the lower control arm by removing the connecting rod clip. Move components aside to access the leaf spring mounting bolts.
   ⚠Ensure air suspension has been fully vented via SDS before disconnecting any air spring components to prevent injury from pressurized air.
3. 3

   Support the rear suspension assembly
   Place a floor jack under the leaf spring (lower trailing arm) near the wheel carrier to support the weight of the suspension components. Raise jack just enough to take load off the mounting bolts. This prevents the suspension from dropping when bolts are removed and allows controlled lowering.
   ⚠The jack is only supporting the component during removal, not the vehicle weight. Do not rely on it as primary vehicle support.
4. 4

   Remove leaf spring rear mounting bolt
   Locate the rear bushing mounting bolt that connects the leaf spring to the wheel carrier. Using a breaker bar and appropriate socket, remove the through-bolt and nut. The bolt passes through the bushing and both sides of the wheel carrier bracket. Note the orientation of any washers or spacers. The bushing will remain pressed into the leaf spring eye.
5. 5

   Remove leaf spring front mounting bolt
   Locate the front bushing mounting bolt that connects the leaf spring to the rear subframe bracket. Remove the through-bolt and nut while supporting the leaf spring with the floor jack. Carefully lower the jack to allow the leaf spring to pivot down and away from the mounting points. The spring can now be removed from the vehicle if needed, or bushings can be pressed out with spring still partially installed.
6. 6

   Remove old bushings from leaf spring
   With the leaf spring removed or lowered sufficiently, transport it to a hydraulic press or use an on-vehicle bushing press tool. Using appropriate bushing drivers that contact only the outer bushing shell (not the rubber), press out the old bushings from both the front and rear eyes of the leaf spring. Clean the bushing bores thoroughly with a wire brush to remove all rust, debris, and old rubber. Inspect the bores for cracks or damage.
   ⚠Never press on the inner sleeve or rubber portion of the bushing, only on the outer metal shell, to avoid damaging the leaf spring bore.
7. 7

   Install new bushings
   Apply a light coat of soapy water or approved rubber lubricant to the outside of the new bushings (never use petroleum-based products). Align the bushing with the bore, ensuring any orientation marks or voids in the bushing are positioned correctly per Mercedes-Benz specifications. Using the hydraulic press and proper size bushing driver, press the new bushing straight into the leaf spring eye until it seats flush with both sides of the mounting eye. Repeat for the second bushing. Verify bushings are fully seated and centered.
   ℹ️Some bushings have specific orientation requirements with voids positioned for articulation. Consult factory service information for correct orientation before pressing.
8. 8

   Reinstall leaf spring front mount
   Using the floor jack to support and position the leaf spring, align the front bushing with the rear subframe bracket. Insert the front mounting through-bolt from the correct side (note original orientation) through the subframe bracket, bushing, and opposite bracket. Install washer and nut but do not torque yet. The bushing must be torqued with the vehicle at normal ride height to prevent premature bushing failure.
9. 9

   Reinstall leaf spring rear mount
   Raise the floor jack to align the rear bushing with the wheel carrier mounting bracket. Install the rear through-bolt, washer, and nut. Verify all washers and spacers are in their original positions. Do not torque yet. Verify the leaf spring moves freely through its range of motion without binding.
10. 10

    Reconnect air spring and sensors
    Reconnect the air spring line to the air spring body, ensuring it clicks into place securely. Reconnect the electrical connector to the air spring. Reattach the ride height sensor linkage rod to the lower control arm and secure with the clip. Verify all connections are secure and properly routed away from moving suspension components.
11. 11

    Reinstall wheel and lower vehicle
    Install the rear wheel and thread on the lug nuts by hand. Lower the vehicle from the jack stands until the full weight of the vehicle is on the wheels but tires are still just touching the ground. This represents normal ride height position.
12. 12

    Torque leaf spring mounting bolts at ride height
    With vehicle weight on suspension at normal ride height, torque the front and rear leaf spring mounting bolts to specification. This is critical because torquing the bushings while suspension is hanging will preload the rubber and cause premature failure. After torquing, finish lowering vehicle completely to ground.
    ⚠Leaf spring bushing bolts MUST be torqued at normal ride height with vehicle weight on suspension. Torquing while suspension is hanging will destroy the new bushings.
13. 13

    Torque wheel lug nuts and reactivate air suspension
    With vehicle on ground, torque all wheel lug nuts to specification in a star pattern. Connect Mercedes-Benz Star Diagnostic and exit Service Mode to reactivate the AIRMATIC system. The system will perform a self-leveling cycle. Monitor for any fault codes or air leaks. Verify the air spring inflates properly and vehicle rises to correct ride height.

Reassembly

1. Repeat entire procedure for opposite side if both bushings are being replaced
2. After reactivating air suspension, perform a visual inspection of all air lines and connections for leaks
3. Clear any stored suspension fault codes using Star Diagnostic after verifying system operation
4. Test drive vehicle and verify proper suspension operation, ride quality, and absence of abnormal noises

Verification

• Verify all leaf spring mounting bolts are torqued to specification with vehicle at ride height
• Confirm air suspension raises and lowers properly without fault codes
• Check for any air leaks at spring connections by listening for hissing sounds
• Test drive vehicle over various road surfaces to verify improved ride quality and absence of clunking or binding
• Verify ride height sensor is functioning correctly and vehicle maintains proper stance
• Schedule 4-wheel alignment as suspension geometry has been altered by bushing replacement

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