Item 1) The adjustment for the P/S gear box is supposed to be done off the car where the effort to turn can be measured. With experience many have done it on the car. I fix a car a month that has been aligned by several shops with no solution, by readjusting the pitman bearing load. I have done hundreds but never saw one where the bolt turned with the steering. In most cases if the 19mm jam nut isn't tightened securely the bolt will leak. I presume you are too far out.
2) The rotors on MBs seldom have more than 1.2mm of wear tolerance. That is .048in. If they are new then there might be enough there to turn. If they have 30k miles they are half way through that tolerance already. They are designed to be disgarded. And they are so cheap that its probably easy to spend more paying to have one turned than to buy new (at least if you are doing your own work). The standard turning roughness also makes poor brakes.
3) Down the back side of the pump is a 14mm jam nut on a long screw. Loosen the jam nut and tighten (clockwise) the screw.
Bosch Master, ASE Master, L1
33 years MB technician