Front Suspension Question -- 420SEL

[Abner Mality]

The vehicle is a 191,000 mile 1990 420SEL. About two weeks ago, I began experiencing a bad vibration at around 65MPH, and every time I braked regardless of my speed. I was needing tires, and I just laid the problem off to bad tires. I purchased 4 new tires on Monday, and the installer told me that the right front probably needed a bushinig on the lower control arm because the wheel was jerking back and forth as he tightened the lug bolts. I made an appointment with my regular alignment guy for this morning, and he pointed out to me where the slack is, but his parts supplier did not show such a piece in his catalog. He thinks MB calls this piece a trailing arm, and that there must be a bad bushing where it terminates at the subframe.

I told him not to sweat the parts; I'll get them from Phil, but it would be nice if I actually knew what part to order. The piece in question connects at the lower control arm, then proceeds at about a 45-degree angle to a cube-looking "box" where it mounts to the subframe. I'd send pics, but it has been pouring rain all day, and my garage is a white oak tree furnished by Ma Nature. Any help would be appreciated.