Mercedes-Benz W220 front ball joints and control arms
Is the W220 front ball joint replaced separately or the whole control arm?
It depends on the joint. The lower control arm ball joint is pressed into the hub with a press. In an Airmatic car the lower-end joint of the strut is an integral part of the control arm, so the whole control arm is replaced. The control arm bush may also not be available separately. After the replacement the wheel alignment is adjusted.
The track rod ball joint won't come out of the hub, what helps?
A puller alone is not always enough. One way is to heat the area around the joint and cool the pin immediately with freezer spray. Another way is a C-clamp, which is tightened gradually while waiting a few minutes. The clamp must not be tightened until it breaks.
The lower-end joint of the strut feels loose, what could cause it?
The play can be in the joint's mounting and not in the joint itself, so check the mounting first. The mounting bolts are long and can seize or snap. Steering and suspension are safety-critical, so have a workshop check the result of the work.