Should I Mess with my Crank Pulley Bolts?

[techguy512]

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

[Larry Delor]

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.

[Motorhead]

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.

[tangofox007]

Originally Posted by Larry Delor

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.

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.

[t walgamuth]

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

[techguy512]

Originally Posted by tangofox007

I'd retorque the crank bolt while I had the pulley and damper off.

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?

[Motorhead]

Originally Posted by techguy512

Am I nuts?

NO.

[tangofox007]

Originally Posted by techguy512

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?

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

[blueranger]

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....

[tangofox007]

Originally Posted by blueranger

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....

That's not the typical failure mode. More commonly, they all shear off. All six at one time.

[Larry Delor]

I have had the large main bolt break on me 3 times. Those six little bolts had nothing to do with it. The three times that it was repaired, it was done so by a professional MB mechanic, and yes, he used a torque wrench and torqued everything to its specification. After the third repair was done, I decided to get a rebuilt engine, since the slots in the crank got damaged to the point to where the last repair wasn't going to last long at all.

So, I suppose if you can't be stopped, you can make sure that the six bolts are not ready to fall out, since if they do, you loose your belts.
And maybe some day (after having had sufficient amounts of beer) I might do the same...However, I sure as all hell won't touch that big bolt - No way Jose - I'll sell the car first.

[Stevo]

I had a pulley come adrift on my 79 so I check them. It doesnt take long to make sure there tight if you have the radiator out.

[t walgamuth]

none of those bolts should just come loose. it is not listed in the mb maintenance schedule to check them for looseness.

imho messing around with them if there is no reason to is asking for trouble.

if you have the urge to check torque on something check your lug nuts!

tom w

[Stevo]

I think keeping undo stress off the pulley is a good idea. Its also bad for bearings to have belts too tight. Checking belt tension is in the MB maintenance schedule

[t walgamuth]

well....belts yes. bolts no.

you're kidding, right?

tom w