Traduzione in corso passo 2
Begin by draining the brake fluid from the system.
You will need to jack up the car, and remove the wheels. See the W123 guide page for help with both of these topics.
Now you can open the bleeder on each caliper to let the fluid drain in to an appropriate drip pan. It will take a while as it will drain slowly. Let it drain until it is barely dripping and the reservoir is empty.