Mercedes Coupes/Sedans/Wagons 1974-1984 Repair Guide

Brake Disc (Rotor)



Brake pads may contain asbestos, which has been determined to be a cancer causing agent. Wear an approved filter mask or respirator whenever working around brakes, to avoid inhaling dust from any brake surface. Never clean brake components with compressed air! instead, use a commercially available brake cleaning fluid.

See Figures 1 through 5

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Fig. Fig. 1: To remove the front disc brake rotor, use a pair of channel lock pliers to pull off the dust cap

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Fig. Fig. 2: 1. Clamp nut 2. Clamp nut retainer Loosen the clamp nut retainer ...

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Fig. Fig. 3: ... then remove the clamp nut from the spindle

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Fig. Fig. 4: Remove the outer wheel bearing from the rotor hub

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Fig. Fig. 5: Remove the front brake rotor from the spindle

  1. Removal for the various types is similar.
  3. On all models, remove the brake caliper. On 1974-76 230, 240D, 300D, 280 and 280C models and on 380SL, SLC, 450SL and SLC models, the hub and disc can be removed by prying off the dust cap, removing the socket screw and clamp nut, and pulling off the wheel hub. Fasten the hub in a vise or holding fixture (be careful not to distort the housing), matchmark the disc and hub, then unbolt the brake disc.
  5. On all other models the disc can be unbolted from the hub.
  7. Inspect the disc for burning (blue color), cracks and scoring. The disc becomes scored slightly in normal service; therefore, replace it only if the depth of individual scores exceeds 0.020 in.
  9. To ensure proper alignment, clean the hub and disc with emery paper to remove all rust and/or burrs, then bolt the disc to the hub.
  11. It is a wise precaution to use new lockwashers under the bolts.
  13. Install the hub and disc, then check the disc for runout (wobble), using a dial indicator as illustrated.
  15. If runout is excessive, it sometimes helps to remove the disc and reseat it on the hub. Install the caliper assembly and bleed the brakes.

If new brake discs are being installed, remove the anti-corrosion paint before installing it.