"I decided to replace my cabin filters, only to discover my '91 300D doesn't have any. But that's not before I had removed all of the seals, bits and bobs around the wiper. It did give me the opportunity to clean the drains... but I broke one of these plastic bolts... any idea where to get them or what the part no. is?"

When I need a part like the plastic bolt, I go to the parts counter at the Mercedes dealer. When you tell them where it's from, they bring up a diagram on their computer screen. You get the part number and the part if they have it in stock. If not, you can get it within a couple of days if they have to order it. Generally, the prices are reasonable in the sense that they are only five dollars or so above what you think you aught to pay.