Replace Crank Vibration Damper?
 

Has anybody replaced the 617 crank vibration damper? I don't have a factory manual and I cannot find a thread for it. Is it difficult once you get the crank pulley off? Does it require any special tools?

I've done it a few times recently and made a thread about it: http://www.peachparts.com/shopforum/diesel-discussion/400337-om617-crankshaft-wobble.html

Long story short, the original was damaged which created a significant wobble. I ended up swapping it out for another original from a different engine - this fixed the issue. Before I knew of the culprit, I believe I took it off and reinstalled it a handful of times. IIRC drain the radiator, remove the top hose for the radiator, remove the radiator fan followed by removing the fan shroud, loosen power steering pulley adjustment, loosen alternator belt adjustment. The pulley for the radiator fan will come off fyi just set it aside - the radiator can remain in place, just drain it first though. Other than that, you just have about 5 or 6 allen head bolts to unscrew that hold the damper to the crankshaft. Do not strip these or you're going to have a tough job ahead of you, I would make sure the bit fits in the head of the bolts snugly before unscrewing, oh yeah and you'll also have to wedge a socket in between the harmonic balancer and block in order to unscrew the bolts without the crankshaft spinning. I can maybe outline this better for you if you don't understand - other than that you're good to go

Okay, the six bolts get the crank pulley off, but how does the pulley come apart to replace the rubber damper? is it just held together by the six bolts, or does it need a special puller to separate the pulley from the rubber damper?

Just held by the bolts, you might just have to wiggle it off there is no need for a puller. Also make sure to use thread locker when reinstalling - not the red kind. The pulley itself would have to be taken to someone who rebuilds them - there's no way you'd be able to replace the rubber component if that is what you're asking

Buy a new one if you can find it. That rubber deteriorates with heat, oil and fuel. When it goes it will allow the pulley to spin. Mine never came off but I shut the engine down when the alt light came on.

I bought one about 8 years ago from worldpac after installing one off a junk car and finding it wasn't much better than the original.