Cup holders in the dash are known to break requiring repair or replacement.Google+
Car Problem Reports
Mercedes-Benz CLK55 AMG Cup Holders in Dash May Break
Mercedes-Benz CLK55 AMG Problem
Average Mileage: 70,243 mi (33,333 mi - 119,000 mi)
Visitor, 2004 Mercedes-Benz CLK55 AMG, 78,640 mi
Cup holder won’t retrieve back. stuck. I clean it with alcohol swab and still won't work.
spring and plastic piece that clamps holder around cup ...shit the bed 125 fro the holder 400 in labor. Take the dash out to replace.