All I have found on the forum is that the crank bolt size on a 190 or something is 27mm. Is it the same for a OM617? I need to know quick so I can go buy one before they close. Sears or auto parts store?

27mm on a 617. (Head size, not bolt size.) The bolt is a M18 x 1.5 x 45. But you definitely won't find one at Sears or most parts stores.

Or are you looking for a socket?

thanks! ya head size.... damn pulley is is either loose or needs a new damper/balancer or whatever they are called on the om617.

will the "starter bump" method work to get the bolt loose? Works like a charm on the SHO
Thanks

Save yourself some trouble and check the pulley first. The pulley is bolted to the balancer by six socket head cap screws. (Maybe 5, depending on which model 617.) The damper is sanwiched between the pulley and balancer. (Maybe 5, depending on which model 617.)

Unless the entire assembly is loose, the is no need to loosen the crankshaft bolt.

ummmm.... ok thats sounds good to me. I cant seem to get to the front of the pulley because of that darn fan in the way. I also can not seem to figure out what size "bolt heads" are attaching that fan/clutch to the water pump. I basicallt need to remove the fan to get a clear shot at the crank.

you mention screws(?) holding the pulley/dampner/balancer ass'y together? Is this right. So I should look at those first you say? I would say that the part of the the cranl pulley that has the timing marks on it seems solid but the pulley wobbles very bad. I thought it was a bad water pump and was trying to remobe the belt to get to it... then I noticed the pulley moving!

Than belts seem to be a PITA to even deal with.

Thanks again

All the more reason to check the pulley screws. This could be your lucky day. You would much rather have a loose pulley than a loose balancer.

The fan clutch bolts have 10mm heads. You might need to grind a box-end wrench down a bit on the outside in order for it to fit. Using an open-end wrench runs the risk of rounding off the bolt heads.

Well it's been a long day. This was my first semi major MB repair EVER! I only got through 2 beers and thanks to my trusty VW golf I made 2 trips to the auto parts store and one to home depot. Oddly enough none of the auto parts stores in my immediate area had these bolts... I found them at home depot. I use to always see engine studs and bolts at lowes/home depot and always wondered why anyone would buy them from a hardware store. Now I know. Advance auto/O' Reilly's you officially suck now!

It started as a clanking noise that got louder and louder(in another post somewhere) in the span of one day. I parked it and sorta put it on the back burner. Today I pulled the valve cover and checked my valve adjustment job and timing chain wear. My timing marks on the crank point sorta at 5.5 just past that little stud on the crank/pulley or whatever. I am still kinda unsure on if the chain needs replaced or not

After the top end checked out I started on the belts to isolate accessories... I then noticed 1: the belts are a PITA if you have never done it and 2: the crank pulley was all over the place when running. I could move it would my hand, when it wasn't running. Remember it was only two beers

TangoFox007 helped me out on the forum and I discovered the bolts, below, were is bad shape. Only one bolt was semi tight. The other complete bolt was just sitting in it's place holding on by a thread and some gunk. The other 4 bolts were sheared off and only being held in by gunk and grime. I got the pulley/damper thingy off and had to sit for a while with a screwdriver and a small hammer(dykes... or diagonal pliers if you prefer) and back the studs out of the crank flange(? I dunno what to call it).

Anyway it's all put back together now thanks to the forum. A little locktite on 4 of the new bolts for good measure and I am happy.

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Hopefully, the replacement bolts are the same length as the original. If they are too long, they will damage the front crankshaft shield.

They are the exact same size. I know.. who knew home depot had MB engine bolts. I wonder if they are the same strength or not. I am guessing that the car would work just fine with half the bolts missing.. so if one breaks I will replace all six with OEM bolts. The worse that can happen is all six break and the pulley goes bouncing down the highway. Seeing things like that make me laugh a little. I had a rear bumper fall off a truck of mine once and it was all I could do to keep it on the road I was laughing so hard. I had to go back and get the bumper cause it had my plate on it.

Thanks again

The original bolts are 8.8. The ones at the hardware stores are usually 12.9.

like I say, if they break they break. I am sure I can find AN hardware for it too. No chance in aircraft hardware being weaker than automotive stuff. I have a background in aircraft maintenance btw. So far the old 300SD is somewhat similar to aircraft. built tough and simple systems

There is also no chance that you are going to find A/N hardware in metric sizes!!!

I thought of that while taking a shower.. guess I could tig weld it on there