idler arm pivot question

[Graham]

THis is on an early R107, but steering is similar to other early Benzes so asking here.

With front wheels off ground, if I turn front wheels so as to actuate the steeing linkages, I hear a groaning from the idler arm pivot.

My question is about the design of that pivot. It has steel sleeves set into rubber bushings that fit into a large tube that is attached to the chassis frame.

It looks like there is no keyway, spline or other method of locking the idler arm to the pivot bolt. (I haven't removed it to confirm that!)

Does the arm just rely on compression of the inner sleeves to lock the arm to the bolt and the metal sleeves so that the sleeves move with the arm? And if so, presumably the sleeves turn inside the rubber bushings? If so, perhaps the groaning rubber on metal sound is normal?

Somehow, I thought the arm should be locked to the bolt and it should turn inside the metal sleeves. But it doesn't look like it works like that!

By the way, on my car the bolt head is at the bottom. Same on a few other similar cars. But all parts diagrams show it as does the picture from the FSM below.