Going over large bumps in convertible models may cause the roll bar to deploy, rendering the roof inoperative. Special tools are generally required to return the roll bar to its stowed position.Google+
Car Problem Reports
Mercedes-Benz CLK550 Going Over Bumps in Convertibles May Cause Roll Bar to Deploy
Mercedes-Benz CLK550 Problem
Visitor, 2009 Mercedes-Benz CLK550, 32,020 mi
The rollover protection headrest will deploy sitting still!!! Sometimes after cornering they will deploy. Today, I parked at the credit union and about 2-3 minutes AFTER stopping (normal, smooth stop from 25 mph!!), they deployed! Last year after having been in storage, the dealer charged the battery and I had no more problems. Got NO idea why that matters...the car starts, runs, fine, no apparent low battery indications like blower slowing down when turning headlights on, etc! Weird!
Visitor, 2007 Mercedes-Benz CLK550
Mine is a 2005.
My local gas station mechanic can fix this... especially when the top is already down. He simply inserts a long screw driver next to the rear headrests and hits a release that lets each headrest go back down, ready for the next time.