Ok, I got the alternator off . Those two mounting bolts will go back with some anti-seize compound on the the threads. I removed the nut from the alternator and did not find any kind of lockwasher (eg. serrated washer etc) behind it ( nut>pulley> alt fan> thrust washer), no keyway . Is there supposed to be a lock washer between the nut and sepentine belt pulley on this one (w124 300D)? . - Thanks