Mercedes Benz repair: Belts, pulleys, etc., crankshaft pulley, harmonic balancers

Question
Mr Hunter,

I have an 83 300 D turbo, and last night it began running hot.  
About the same time, the power steering went out, and the
alternator light came on.  When I checked under the hood, I
noticed that the main pulley which drives the fan, alternator,
power steering, AC belts was not turning.  When I turned off the
motor and wiggled it, I noticed that the main pulley was a bit
loose.

Is it possible that the main bolt which holds it onto the
crankshaft got loose some how?  When I got the car it had bad
engine suspension, which I have just finished replacing.  I am
curious if the pulley just worked its way loose, or if there could
me more serious problems with the balancing disc assembly,
etc.

Any ideas on how to troubleshoot this problem and/or repair it
would be greatly appreciated.

Thanks, as always,

RSCarey

Answer
Read all of these threads, and repair may be possible.

Haromonic Balancer: note of caution
http://www.mercedesshop.com/shopforum/showthread.php3?p=158104#post158104

Failed 123 Diesel Harmonic Balancers
http://www.mercedesshop.com/shopforum/showthread.php3?p=115016#post115016

help please with loose part on front of my 300SD's engine
http://www.mercedesshop.com/shopforum/showthread.php3?p=360310#post360310

Crankshaft pully fell off - HELP! I may call it quits.
http://www.mercedesshop.com/shopforum/showthread.php3?p=930060#post930060

Harmonic balancer bolt
http://www.mercedesshop.com/shopforum/showthread.php3?p=305827#post305827

Is it possible to retap the 27MM crankshaft pulley hole where bolt fastens?
http://www.mercedesshop.com/shopforum/showthread.php3?p=600051#post600051