Have you checked the steering linkage? There might be tired tie rods, drag link or idler arm bushings. Are any tie rod or drag link end boots torn?

86 and 87 have the benefit of replaceable ball joints. It costs less in parts to get LCA bushings and ball joints separately. Obviously more work. If you get control arms with integral ball joints, it's shouldn't have to be said but you won't be able to replace just the ball joints in the future. Whichever way you go, get proper replacement parts. Either MB brand or OEM built to original specs. Be wary of suppliers such as in the eBay listing that don't specify the manufacturer. This forum is choking on posts of the results of installing substandard suspension parts.

300E steering and suspension parts generally work on a 300D. Springs might be different. Note that MB changed 124 Pitman and idler arms and drag links in 90 or 91. The drag link doesn't interchange between early and late 124s. Later pins are bigger and the drag link itself is a different length.

Sixto
87 300D