rear wiper

I suspect that many owners of a W211T will have a tailgate window, the wiper spindle surround of which looks like this - quite possibly a common problem. My question to our experts is this: is this metal plate available as a separate part, or is it an intrinsic part of the window glass?

Hi all. Don't know if anyone can help me but, when we returned after a month in Australia after all the really poor weather in February, my 220 CDi estate wouldn't start. A friend used jump leads to start it but, stupidly although he attached them the right way round on my car, he put them on...