Warning! Jacking up or jacking up a vehicle can be dangerous. It is therefore recommended that you familiarize yourself with the safety precautions in Chapter "Jacking up a car".
1. Jack up the rear of the vehicle and place it on jack stands.
2. Remove plug 1 from support shield 2 of the brake mechanism (see illustration).
3. Shine a flashlight into inspection hole 4 and check the thickness of the brake pads 5 (see illustration).
The wear limit of the pads is considered to be reached if their residual thickness without taking into account the support plate is 1.5 mm. If it is not possible to determine the residual thickness visually, then remove the brake drum and measure the thickness of the brake pads. If at least one brake pad lining has reached the permissible wear limit, then all four linings on all pads are subject to replacement.
4. Replace the inspection plug on the brake shoe support plate.
Original source of information (www.mercedesman.ru)
5. Check the remaining thickness of the brake pads on the brake drum of the second rear wheel.
6. Lower the car onto its wheels.