The brushes are part of the entire regulator unit. Replacing the regulator is easy - look for a small plastic panel on the back of the alternator with two Philips screws in it. It will probably be white in color. It will be on the back of the alternator (facing the engine firewall). Unscrew the two screws and the regulator assembly (including brushes) can be lifted out.
A new regulator should be cheap and it installs easily. Just guide the brushes into the alternator, align the unit and screw it back in with the same two screws. Make sure you don't damage the brushes when installing the regulator. You may have to play with the unit a bit to get it to fit into the alternator (the brushes will be taller than your old unit), but it will fit in properly, you shouldn't have to fight it. Good luck!
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired
"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon