I recently did this job on my 1984 300SD, and paid a machinist about $70 or so to press out the old ball joints (from the steering knuckle) and press in the new ones.
On my car, they are pressed in at an angle that makes using most ball joint tools ineffective. There are places that will rent you the MB tool (manufactured by SIR) but I decided against that option as the price differential was not that great and didn't want to wait for the tool to arrive.
Not a fun job, but the results were worth it. I also replaced the track rod mount bushings at the same time and the front end is now very quiet and feels new again.
1984 300SD 141.4k