Applies to most (but not all) older Mercedes 1973 to 1993.
I have heard some owners complain about the unreliability of those older Hirschmann power antennas. I would say that in at least 80 percent of the few hundred antennas I have taken apart that went bad - the reason was lack of lubrication! When the mast does not get cleaned and wiped with lubricant on a regular basis it puts excess strain on the motor and the mast retract mechanism. Lack of lube on the mast also helps to allow water to get down inside the antenna housing and that causes all kinds of problems.