The parking brake adjusting sprocket can be accessed with a screwdriver through the hole for the wheel bolt
1. Remove one bolt from each rear wheel. Raise the rear of the vehicle, first securing the front. Release the parking brake completely.
2. Turn the wheels so that the toothed adjusting disk is visible in the bolt hole. Insert a screwdriver and turn the adjusting disk until the wheel is braked, then back it off by 2-3 teeth so that the wheel can rotate freely.
3. After making the same adjustment on the second wheel, lower the car, tighten and secure the two bolts.
4. Tighten the brake actuator, determining the number of clicks required to fully tighten it. If this number is too high, adjust the cable tension by turning the equalizer screw located behind the gearbox. The screw eye should always be in a vertical position.
Information copied from the website: www.MercedesMan.ru