Date registered: Mar 2017
Vehicle: 1984 380SL
Location: North America
Mentioned: 6 Post(s)
Quoted: 597 Post(s)
How's the health of the belt?
A loose belt might not provide enough for the pump.
Or because you didn't drive the car for a bit, the grease in the boots on the steering linkages need to be redistributed. Or a lower end component or bushing has gone bad in that same location.
If the belt looks ok, I would keep driving the car and see if it goes away. Remember, these vehicles don't like sitting. They need to be driven or else they get cranky.