Mercedes-Benz W211 control arm ball joints
Can the upper ball joint on a W211 be replaced separately?
Only if the upper ball joint is held on with bolts and nuts. On the original control arm the ball is cast into the arm, so the whole control arm is replaced. A riveted upper ball joint has not been seen on any 211-body car.
How is the lower control arm joint on a W211 replaced?
The joints of the wishbone-type lower control arm can be replaced in the arm: the old one is pressed out with a press and the new one pressed in. Front-end clunking has gone away with a joint replacement, and the arm did not need to be replaced. The ball joint of the reaction rod usually comes with the rod.
How do you separate a seized ball joint?
A tight tapered joint needs a proper ball joint puller, because cheap ones break. The joint often comes loose more easily when it is struck from the side without a puller. Soaking a seized inner bolt in rust remover overnight can help.
Is wheel alignment needed after replacing a control arm?
Yes, a wheel alignment is done after the replacement, and removing the control arm requires a four-wheel alignment. New ball joints are not greased, because the installation instructions forbid it. Suspension work is safety-critical, so have a specialist workshop check the result.