I don't see why you would want the rail to wobble. Isn't the purpose to steady the chain after it makes the turn around the crank? The tensioner is responsible for keeping the chain tight. And it seems to me that MB would have spec'd a pin-type bolt had they wanted it to wobble, and not relied on a finger-tight fully-threaded bolt.

My $.01.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe