I need some basic education on rubber bushed joints in suspension systems. I have a ’84 300CD and the inner lower control arm joint is worn. This is evidenced by the rubber bushing not being square in between the mounting plates on the unibody. My question is, on this joint, which two parts move against each other when the control arm moves up and down? Which parts need lubrication? The tube sleeve is so thin walled that it is hard to believe that it can stand movement. But it seems that it must be involved with the motion of the joint unless the rubber bushing rotates in the control arm.

Please help me to understand how this joint works and what needs lubrication and what does not. That would really help me to understand rubber bushed joints in general!

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1984 300CD (sold)
1973 220DPK 4 spd (died)
1978 350SL 4 spd gray market
2003 SLK32 AMG
1988 300CE (sold)
1997 E420 (Totaled)
1998 E320 Wagon