Heard lots of horror stories about sheared bolts at the crank pulley.

I'm going to have my radiator and condenser out this weekend, and I'm
planning to replace all my drive belts, etc. Should I do anything about the
six bolts at the crank pulley? Here are the options as I see them:

1) replace 6 bolts on principle
2) remove, inspect, locktite and retorque the 6 bolts
3) retorque only
4) none of the above, but something
5) nothing

Appreciate any input.

Bob
'82 300D

If it aint broke - Don't fix it.


in other words: #5

Besides, it's not just the 6 bolts....It's the big ole bolt in the center...that, can be the real PITA.
Inspect yes, but I wouldn't touch them....I wouldn't even look at them funny, or stare too long at them.

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

I have worked on alot of 4 and 5 cly mercedes. I haven't personally seen any failures but Murphy's Law can come up and bite us at any time. It wouldn't hurt to check the bolts and re-torque them. If they are loose, I would deffinately ck them for stretch and replace them if that were so. MAKE SURE that if you are replacing the bolts that you are buying the same "HARDNESS" as the origional bolts. Metric bolts are graded like SAE bolts.

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

I am a big believer in fixing things before they break. That way I get to work on my terms, not on the side of the road on a cold, rainy night.

The six pulley bolts can be removed and replaced with out touching the crankshaft bolt. But if it were me, I'd retorque the crank bolt while I had the pulley and damper off. And maybe think about changing the front crankshaft seal, since your already halfway there!!!

My original pulley bolts were M8 x 30, grade 8.8. Just don't get too carried away with the thread locker. Those socket heads are easy to strip, if you ever need to take them out again.

i'm with larry.

and if the front seal is not leaking no way would i replace it. it may last another 100k.

monkeying around with things that arent broken is asking for trouble, imho.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I was planning to leave the pulley and damper on, and just checking the hex bolts. If loose, inspect and replace if necessary, but retorqe all.

Am I nuts?

NO.

__________________
My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

There is nothing wrong with that, if that's all you want to do.

if it ain't broke dont fix it...

if those bolts come out they come out one at a time... so just keep your eye on them....

Stick with #5..

I just did this all on my dad's '83 SD....we had to pull the pulleys and vibration disc to get at the pin for the chain tensioner. I put the big main bolt back in and torqued it to about 220ft/lbs or so.....and the smaller M8x30 bolts were replaced with a new set from the dealer, the new ones are 10.9 hardness....old were 8.8. I used blue locktite in the reinstall, and torqued them to 25nm like it says in the FSM.

Its not *that* scary....taking off the camshaft sprocket and chain/tensioner and such, is scary! And I did all of that too, successfully. The engine was fired up today and runs great.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I was going through my previous owner's records when I purchased my car and I noticed this very thing happened to my car on the previous owner; all the crank pulley bolts sheared off. Needless to say, I'd stick with #5....and that's why I have AAA.

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1984 300D, 228k, Light Ivory, Java MB-Tex

Post #5 relates to a leaking front seal; that is an issue totally unrelated to loose/sheared pulley bolts. Given the magnitude of the problem, I think every 616/617 engine owner would be well advised to check the pulley bolts for tightness periodically.

Sudden loss of power steering might call for more than AAA. Life insurance comes to mind.

Post #1
choice #5) nothing

The original bolts are generally OK until disturbed..

Let's stipulate to that theory. Now, how does the typical owner of a 25-30 year-old (more or less) vehicle determine whether said bolts have ever been disturbed?