The brief
The E200 came in with a knocking sound from the front while driving, and a check turned up a battery on its way out too. Two jobs, both worth sorting in the one visit: a knock over bumps that points at worn suspension joints, and a tired battery that ends in a no-start. The knock traced to the front anti-roll bar drop links, the short rods with ball joints connecting the anti-roll bar to the front suspension; the ball joints wear, go loose, and knock over every bump. The battery just wears out, the capacity drops, and on a Mercedes the new one has to be the correct AGM type and registered to the car's energy management. So it was a drop link pair and a battery replacement.
The diagnosis
On the lift the front suspension got the once-over: the anti-roll bar drop links had worn ball joints with play you could feel, the cause of the knock, the rest of the front solid. The battery test had it down, failing the load test and unable to hold voltage, the alternator charging fine. So it was a front anti-roll bar drop link pair plus a battery replacement, the correct AGM type, fitted and registered.
The work
Both front anti-roll bar drop links were unbolted and removed, and a new pair of genuine Mercedes-spec links fitted, the ball joints torqued to the manual figures and seated. The old battery was removed and a new genuine Mercedes-spec AGM battery of the correct type fitted, the terminals cleaned and the clamp torqued, then registered to the car's energy management and the low-voltage faults cleared. A road test confirmed the knock was gone, the front end quiet, and a strong, clean crank with steady voltage.
The outcome
No more knock from the front, the anti-roll bar working properly, a strong start on a fresh battery registered to the car, and both jobs off the list in one visit. The E200 went home sorted. Worn drop links only knock louder and a tired battery into a no-start, so doing both properly with genuine parts kept them from becoming roadside problems.
