It has to have a bleeder valve and you are going to have to find it to bleed your brakes when you are done. I am not trying to slam you but I am a bit worried for your safety and fellow drivers' safety if you are working on your brakes and cannot find this. Maybe you need to find a shop to help you out?

http://www.benzworld.org/forums/w202-c-class/1201406-brake-job-99-c280.html

http://www.slk32.com/pages/brakes/brakes.html