Lower alternator bolt size (Early W123)
 

Car's been audibly rattling a lot at low/high RPMs where the engine is shaking the most (cold, on the freeway/above 55 MPH). Looked under the car and found the alternator hanging fine...minus the lower through-bolt. :mad: Second time I've had problems with alternator bolts; about a month ago the upper bolt kept trying to back out after loosing the nut (didn't get sheered off by the fan, thankfully). That time I just took a spare nut from a bad starter motor and stuck it on there (perfect fit ;) ). Now I need a new bolt+nut. Anyone wanna take a guess or give an exact measurement of it? Should be something I can just pick up at a hardware store? Or do I have to pay $2.00 at PNP just to (try) and find one? :o

Also, good or bad idea using threadlocker on these...?

Not positive on size, but your easy way....is probably going to pick n pull....all the bolts are the same length and the top is the same....so worse case remove it and measure...someone said you can pick one up at the dealer for 8$..

You should work on the vibration and audible rattle....kind of sounds like the air cleaner housing mounts may have broke too..

Yeah, better get the correct one.