NSWEuroCharged

No garden......................highly suspicious !

Shifter

I have seen stock pulleys fail as well. More than once on customer cars.

Ls1toAMG

As far as bolt tq is concerned it 40 ft lbs. there is a lot of mis information on line. Unless I'm mistaken even the most common vender of this platform has the wrong tq on their site. It's not even close. 25 ft lbs off. Do your home work. The gap is .35. I would feel fine with .60 or below. Supposedly it gets less after,it runs for a while.

06cls55amg

how long did you have this pulley on for ? i got about 5k on mine, and now have added another thing to worry about to my list lol. are there any signs before it goes? i dod not have a scattershield either, never heard of one. looks like i should look into this. what can i check to insure this doesnt happen? retorque bolt and check gap again?

latemodel21

If some of these failures were related to the bearing failing due to over-torque or the pulley becoming UN-secured due to under-torque ... then I would be more pre-occupied with that value. Anything over 50 foot pounds should be fine.

If the pulley is of reasonable quality, then the gap should not change (nor EVER be a function of bolt torque) ... if the gap is changing then the springs are not bringing the pulley back to it's original "at rest" position ... bringing their life expectancy into question.



as far as what to look for, you should look at the rivets (that are at the pressure plate end of the 3 springs). Look for the rivet head cracking and the spring cracking where that rivet passes though.

here is one about to fail (below) and if you look at post 34 in this thread , you can see one that has "Just failed"


both of these pictures are of an OEM pulley , so the situation may be a little different on yours (in that on some aftermarket pulleys, the spring may crack before there is any evidence of failure on the rivet as a result of trauma to the spring related to sub-standard rivet installation).


cheers,
Chris

nafania

This one is aftermarket one. 83-84mm.
Didn't do any damage.

Hulk

I have seen the pulley gap be way too much which puts a lot of stress on the springs so make sure it's gapped properly

latemodel21

this is an interesting and fortunate failure. Clearly on this spring, the transition to radius at the end (where the rivet attaches) was not smooth enough, creating a stress-riser and causing the spring to eventually fail at the transition, rather than at the rivet.

The good news is, the other end, which too often does not hold the spring tightly enough to avoid "sawsall mode" ... held ... very lucky. The typical outcome (particularly when using aluminum for this sort of pulley application) is that the spring swings out and tears stuff up.