From 1987 models on*, the front brake caliper piston diameters were changed to 44/36 mm (previously 42/36 mm). During the 1989 model year, a further modification was introduced. The piston seal was changed from the scraper ring type to the protective cap type. (Technical Information Gr. 4 No. 1/89) Notes on replacement: refer to Pages 47-04 / 47-05.

* On some cars (those for the USA, Canada, Australia and Arab countries), fixed calipers with piston diameters of 42/36 mm were still used in the 1987 model year. For notes on replacement, refer to Page 47-04.

4. Installing new damper plates in the pistons.

When installing, make sure that the internal diameters of the spring and piston are correctly matched together (Technical Information Gr. 4 and Part List).

The damper plates should engage in the pistons when light pressure is applied, but must not be too ioose (no radial play is permissible).

The damper plates are provided with an adhesive and protective foil.

The protective foil must be pulled off before installation.

5. Insert the brake pads. Make sure that the correct grade of brake pad is used.


When damper plates are installed, the brake carrier plates (back of brake pads) must not be greased.

However, to prevent the brake pads from corroding and seizing in the brake caliper, the seat and guide faces (arrows A) are given a thin film of grease.

Use Optimoly HT (Cu paste) or Plastilube (Schillings Co., P.O. Box 1703, 7080 Aalen, Federal Republic of Germany) for this purpose.

1 Piston

2 Noise suppressor

3 Brake pad without lubricant or grease

6. Grease the spreader spring retaining lugs with Optimoly TA or Plastilube. If new spreader springs are installed, the flat side should face the brake disk, if wrongly installed," correct brake pad seating cannot be guaranteed and the raised section in the center of the cross will rub against the brake disk.

Press the spreader spring together in the center and insert it. Make sure that spreader springs engage correctly (arrow). Do not force the spreader spring into position or the retaining plate may be damaged.

Brake disk

7. Press the warning contact(s) into the pad plate in the correct positions. Secure the warning contact lead to the brake caliper and, if two warning contact leads are present (from 1989 models on), to the cross spring as well.


If tolerances are unfavorable, the spreader spring may have to be disengaged again to do this.

8. With the car standing still, depress the brake pedal firmly several times, so that the brake pads adopt a position ready for later operation. After this, check brake fluid level in the reservoir and add more fluid if necessary.

Running in the brake pads

New brake pads need to be used for about 200 kilometers before they develop their optimum friction and wear characteristics. During this time, avoid full brake applications from high speeds unless an emergency arises.

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