Drum Brake Hardware Kit

This procedure replaces the drum brake hardware kit on the rear brakes of a 2007-2013 Mercedes-Benz S65 AMG, including springs, clips, adjusters, and related components.

Warnings

Tools required

Parts

• Drum brake hardware kit (springs, clips, adjusters) × 2 — Use OEM specification
• Brake drum (if worn beyond specification) × 2 — Use OEM specification
• High-temperature brake lubricant × 1 — Use OEM specification

Fluids

• DOT 4+ Brake Fluid — 0.5 qt

Preparation

1. Verify vehicle is actually equipped with rear drum brakes (some S65 AMG models have rear disc brakes)
2. Park vehicle on level, solid surface and engage parking brake firmly
3. Place wheel chocks in front of front wheels
4. Loosen rear wheel lug nuts 1/4 turn while vehicle is on ground
5. Raise rear of vehicle using floor jack at approved lift points
6. Support vehicle on jack stands rated for at least 3 tons per side
7. Remove rear wheels completely
8. Prepare clean workspace with parts trays to keep left and right side hardware separate

Procedure

1. 1

   Release parking brake and remove drum
   Release the parking brake inside the vehicle. If drum is stuck, apply penetrating oil around the drum hub interface and wait 10-15 minutes. Use drum removal tool or slide hammer attached to wheel studs if necessary. The drum may be seized by rust or brake shoe contact. If drum will not release after moderate effort, there may be a rear inspection plug to manually back off the adjuster wheel through the backing plate.
   ⚠Do not strike the drum with a hammer as this can damage wheel bearings or ABS tone rings on this vehicle.
2. 2

   Document original configuration and inspect components
   Before disassembly, take clear photos of the brake assembly from multiple angles showing spring positions, adjuster orientation, and component relationships. Inspect brake shoes for contamination, drum for scoring or excessive wear (measure diameter if possible), and wheel cylinder for leakage. Note any abnormalities before proceeding.
   ℹ️If wheel cylinder shows any signs of leakage, it must be replaced before installing new hardware.
3. 3

   Remove return springs
   Using brake spring pliers, carefully remove the upper and lower return springs connecting the brake shoes. These springs are under significant tension. Work methodically, starting with the spring end closest to the anchor point. Keep your face and hands clear of the spring path during removal. Place removed springs in parts tray labeled for disposal.
   ⚠️Brake return springs are under extreme tension. Improper removal can cause springs to fly off at high velocity, causing serious eye or facial injury.
4. 4

   Remove hold-down springs and pins
   Using the brake hold-down spring tool, compress and rotate each hold-down spring retainer 90 degrees to release it from the backing plate pin. Remove the springs, retainers, and pins from both brake shoes. Keep track of which components go with which shoe if they are not identical.
5. 5

   Disconnect parking brake cable and remove shoes
   Disconnect the parking brake cable from the parking brake lever on the rear shoe. This typically involves unhooking the cable end from the lever arm. Remove both brake shoes as an assembly, noting the position of the adjuster mechanism connecting them. Separate the shoes and remove the adjuster components, adjuster spring, and any connecting clips.
6. 6

   Clean and inspect backing plate
   Spray the backing plate thoroughly with brake cleaner, allowing dirt and old lubricant to drain away. Use a wire brush to clean the shoe contact pads on the backing plate (typically 6 raised platforms where shoes ride). Inspect backing plate for cracks, damage, or excessive rust. Check wheel cylinder mounting bolts for tightness and verify wheel cylinder is not leaking.
   ⚠Ensure brake cleaner is fully evaporated before applying new lubricant to prevent contamination.
7. 7

   Lubricate backing plate contact points
   Apply a thin layer of high-temperature brake lubricant to the six shoe contact pads on the backing plate. Also apply lubricant to the anchor pin where the shoes pivot, and to any slide points for the parking brake lever mechanism. Use lubricant sparingly - excess can contaminate brake linings.
   ⚠Never apply lubricant to brake shoe friction surfaces or drum braking surfaces. Keep lubricant only on metal-to-metal contact points.
8. 8

   Install new hardware kit components on brake shoes
   Using your reference photos, install the new adjuster mechanism, adjuster spring, and connecting hardware between the brake shoes according to the hardware kit instructions. Ensure the adjuster wheel is in the fully retracted (shortest) position. The adjuster typically has a left-hand thread on one side and right-hand on the other - verify correct orientation for the side being serviced.
   ℹ️Left and right adjusters are often different and not interchangeable. Verify correct side before installation.
9. 9

   Install shoe assembly and hold-down hardware
   Position the shoe assembly onto the backing plate, engaging the shoes with the wheel cylinder pistons at the top and the anchor at the bottom. Connect the parking brake cable to the parking brake lever. Install new hold-down pins through the backing plate from the rear, then secure with new hold-down springs and retainers, compressing and rotating 90 degrees to lock.
10. 10

    Install new return springs
    Using brake spring pliers, install the new lower return spring between the shoes, then the upper return spring. Follow the exact configuration shown in your reference photos. Ensure springs are fully seated in their mounting holes or slots on the brake shoes. Verify both shoes are properly positioned against the anchor pin and wheel cylinder.
    ⚠New springs have very high tension. Use proper spring pliers and maintain control throughout installation.
11. 11

    Pre-adjust brake shoes and install drum
    Using a brake adjustment gauge, measure the inside diameter of the brake drum. Adjust the adjuster wheel to expand the shoes to approximately 0.5mm less than the drum diameter. Alternatively, expand shoes until drum slides over with very slight drag. Clean the drum interior with brake cleaner. Install the drum, ensuring it seats fully on the hub. The drum should rotate with slight resistance.
    ℹ️Proper pre-adjustment is critical for self-adjuster function and prevents excessive pedal travel on first application.
12. 12

    Repeat procedure for opposite side
    Perform steps 1 through 11 on the opposite rear wheel. It is critical that both sides are adjusted to the same specification to prevent brake pull. Use the same measurement and adjustment techniques on both sides.
13. 13

    Install wheels and perform initial torque
    Install rear wheels and thread lug nuts by hand until snug. Lower vehicle until wheels just contact ground but suspension is not loaded. Torque lug nuts to specification in a star pattern.
14. 14

    Final adjustment and brake system verification
    Lower vehicle completely and remove jack stands. With vehicle on ground, pump brake pedal 15-20 times to seat brake shoes and activate self-adjusters. Pedal should become firm. Check brake fluid level in master cylinder reservoir and top off with DOT 4+ brake fluid if necessary. Test parking brake operation - it should hold vehicle on an incline.
    ⚠️Do not drive vehicle until brake pedal is firm and consistent with proper feel. If pedal is soft or goes to floor, there is air in the system or a component failure.

Reassembly

1. Final lug nut torque should be verified after driving 50-100 miles
2. Brake adjustment will continue to optimize over the first several brake applications as self-adjusters function
3. If brake pedal feel is not normal, bleeding the brake system may be required even though hydraulic components were not disconnected

Verification

• Test drive vehicle in a safe area at low speed (under 15 mph) and verify brakes engage smoothly without pulling to either side
• Perform moderate brake applications from 30-40 mph on a clear road and verify straight-line stopping with no vibration or noise
• Verify parking brake holds vehicle on a moderate incline
• Check for brake drag by spinning rear wheels by hand after test drive - wheels should rotate freely with only slight resistance
• Re-check brake fluid level after test drive and top off if necessary
• Listen for any abnormal noises during brake application
• If equipped with ABS/ESP, verify no warning lights are illuminated on instrument cluster
• For the first 200 miles, avoid hard braking to allow hardware to seat properly

Related trouble codes on this vehicle

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