The AIR pump has a double bolt set-up. First loosen the smaller (inner) bolt, then turn the larger (outer) to adjust. The larger bolt should also have a star gear to permit a specific amount of travel. I can't remember the sizes but the smaller looks to be about a 13mm, larger maybe a 17mm.
As for running without the pump, it shouldn't hurt anything. The pump only actually functions for the first few minutes on cold start. Once the thermo valve warms up the vacuum supply to the pump is cut and the clutch disengages. Only there to prove extra O2 during warm up.
Hope this helps.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.