CV Boot - Outer

Replace the outer CV boot on the rear axle halfshaft to prevent contamination and damage to the CV joint.

Warnings

Tools required

Parts

• Outer CV boot kit with clamps × 1 — Use OEM specification
• CV joint grease (usually included in boot kit) × 1 — 80-100g molybdenum disulfide grease
• Axle nut × 1 — Use OEM specification - single-use

Preparation

1. Park vehicle on level ground and engage parking brake
2. Loosen rear wheel lug nuts while vehicle is on the ground
3. Raise vehicle and secure on jack stands at manufacturer-specified lift points
4. Remove rear wheel on side requiring service
5. Clean the work area around the CV joint and halfshaft with degreaser to prevent dirt contamination during boot replacement

Procedure

1. 1

   Remove axle nut
   Have an assistant apply the brakes or use a pry bar to prevent wheel hub rotation. Using a breaker bar and 32mm socket, loosen and remove the rear axle nut. This nut is single-use and must be replaced during reassembly.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)
2. 2

   Remove brake caliper
   Remove the brake caliper mounting bolts and carefully hang the caliper from the suspension using wire or a bungee cord. Do not let the caliper hang by the brake hose. The brake rotor can remain in place or be removed for better access.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
3. 3

   Disconnect halfshaft from differential flange
   Locate the six CV bolts connecting the inner CV joint to the differential output flange. Mark the orientation of the halfshaft to the flange for proper reassembly alignment. Remove all six CV bolts using a T40 Torx bit or appropriate socket. Support the halfshaft to prevent it from dropping.
   ⚠Support the halfshaft weight to prevent damage to the outer CV joint and wheel bearing.
   Torque spec

   CV Bolts82 Nm (61 lb-ft)
4. 4

   Remove halfshaft from hub
   Pull the wheel hub assembly outward while simultaneously withdrawing the halfshaft splines from the hub. If the shaft is stuck, use a plastic mallet to tap the end of the shaft while pulling. Once free, carefully lower the halfshaft and support it on a clean workbench or suspend it to prevent inner CV joint damage.
5. 5

   Remove damaged outer CV boot
   Using diagonal cutters, cut and remove both boot clamps from the outer CV boot. Slide the damaged boot off the CV joint toward the center of the shaft. Use a wire brush and degreaser to clean old grease from the CV joint housing, balls, and cage. Inspect the joint for wear, pitting, or damage. If the joint shows damage, the entire halfshaft should be replaced.
   ℹ️Mark the position of the CV joint on the shaft before removal if you need to disassemble the joint completely. Most outer boots can be replaced without joint disassembly.
6. 6

   Clean and inspect CV joint
   Thoroughly clean all old grease from the outer CV joint using degreaser and rags. Rotate the joint through its full range of motion and inspect for smooth operation. Check all ball bearings for pitting, scoring, or excessive wear. Inspect the cage and races for damage. Any roughness or damaged components require halfshaft replacement.
7. 7

   Install new CV boot and clamps
   Slide the new boot clamps onto the halfshaft first, followed by the new CV boot. Position the small end of the boot onto the shaft groove and install the small clamp. Do not fully tighten yet. Pack the CV joint with the supplied grease (typically 80-100g), ensuring grease fills all voids between the balls and cage. Distribute grease evenly throughout the joint.
8. 8

   Seat and secure CV boot
   Slide the large end of the boot over the CV joint housing and into the retaining groove. Ensure the boot is not twisted and sits properly in both grooves. Insert a small flat tool under the boot lip to equalize air pressure and prevent boot ballooning. Position the large clamp and crimp both clamps securely using CV boot clamp pliers. Verify both clamps are tight and the boot cannot be rotated by hand.
   ℹ️Proper boot seating is critical. The boot must sit fully in the grooves without twisting to prevent premature failure.
9. 9

   Reinstall halfshaft to hub
   Clean the hub splines and apply a thin coat of anti-seize compound. Carefully guide the halfshaft splines into the wheel hub, ensuring proper alignment. Push the shaft fully into the hub until it seats. Install the new axle nut hand-tight only at this stage.
10. 10

    Reconnect halfshaft to differential
    Align the inner CV joint to the differential output flange using the alignment marks made during disassembly. Install all six CV bolts and tighten in a star pattern to the specified torque. Ensure the halfshaft is properly seated on the flange before final tightening.
    Torque spec

    CV Bolts82 Nm (61 lb-ft)
11. 11

    Reinstall brake caliper
    Remove the support wire and position the brake caliper over the rotor. Install the caliper mounting bolts and torque to specification. Pump the brake pedal several times to ensure proper caliper piston seating before driving.
    Torque spec

    Mounting Bolts37 Nm (27 lb-ft)
12. 12

    Torque axle nut and install wheel
    Have an assistant apply the brakes or use a pry bar to prevent hub rotation. Torque the new axle nut to 250 Nm (184 lb-ft) using a calibrated torque wrench. If equipped with a cotter pin hole, install a new cotter pin. If using a stake-type nut, stake the nut into the shaft groove per Mercedes-Benz procedure. Install the wheel and hand-tighten lug nuts.
    Torque spec

    Axle Nut250 Nm (184 lb-ft)
13. 13

    Lower vehicle and final torque
    Lower the vehicle to the ground. With the full weight of the vehicle on the wheels, torque the wheel lug nuts to 140 Nm (103 lb-ft) in a star pattern to ensure even seating.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to specification in the correct sequence
2. Verify brake pedal firmness before moving the vehicle
3. Check that the CV boot is not twisted and clamps are secure
4. Confirm the axle nut is properly torqued and secured with cotter pin or staked as applicable

Verification

• Test drive the vehicle at low speed and verify no clicking, popping, or vibration from the repaired axle
• Turn the steering through full lock in both directions while driving slowly to confirm proper CV joint operation
• After 50-100 miles, visually inspect the new CV boot for any signs of grease leakage or boot displacement
• Recheck wheel lug nut torque after 50 miles of driving

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