Does anyone know the size of the bolt at all? Well, getting it out is another issue but what I really need to know also is if an alternative bolt is available...

 

Dude!
That suks!
NeverEnough broke his also. He said that the bolt was hollow inside and was easy to take out with a bolt extractor. Once you find out the size, POST it so we have a record of it.
Dude, that suks!

His story...

 

Hollow inside???????? That has to be a casting bubble and defect. No way do bolts have voids in that size. This is bizzaarr!

Woody

 

They really are hollow. The same thing happened to me when I installed my Code3 pulley and over torqued the bolt. I bet that's why they are hollow. Torque beyond spec and it breaks. Came out real easy and took the two pieces to a local harware store. Found a bolt the same length and threading. Fixed it for about $2.

 

Looks like I'm going to the hardware store after I pull my pulley off this weekend (going to the 181). And from now on I'm gonna be real nice when I tighten the bolt!

 

I'll post a picture of the broken bolt, I still have it...

I replaced mine with a Grade 8 Allen Head bolt from Fastenal. I believe the thread is a 1.25. I have extra, I'll mail you one if you PM me.

 

Ok guys, our size is an M8x1.25 bolt. Lowes stocks M8x1.25 in lengths of 25 and 30 (No, I dont know what the number means exactly, but its 25 and 30).

Both of those sizes are right around our bolt's length, give or take a few millimeters. The 25 is slightly shorter and the 30 is slightly longer. But, my guess is our bolt is the M8x1.25-25 bolt, and my broken bolt appears longer because it lengthens when you twist it as you're breaking it. Because its hollow it seems to twist like scrap metal as its breaking, possibly several turns.

And yes I just jabbed a kitchen knife into the hollow bolt and, due to the sharp knife edge, it grabbed the inside of the bolt and turned it out it easily.

The other issue is I read our bolt's are hollow because they relieve supercharger pressure, I think the oil or something. Its on a benz forum somewhere.... Some said it could be dangerous putting in a solid bolt. No pressure relief. I personally think its just to stop idiots from overtightening and damaging threads. So its possible putting in a solid bolt could be bad, but people have done it with no probs including the MB guys. Either way, I'm doing it.

Woody, if you look at your bolt you'll see a hole in the head. That hole goes all the way through.

And lastly.... My torque wrench only showed 23 ft-lbs when the twisting started. I was just about to stop tightening when all of a sudden torque was gone. I went a few more turns then snap!

 

It is a 1.25-25 M8. I think the OEM bolt is hollow to prevent it from being over tightened. I don't believe the pressure release theory, as only the shaft is hollow. It still has a solid 10mm head, so there is no way it could vent anything. Steel isn't permeable.

 

Being on the aircraft side of maintenance I'm cautious about using any old bolt just because it fits. The bolt may have specific specs for material, hardness, shear and tension strength, etc.

 

That's a very valid point. However, this is really the only practical solution. Both the Benz dealer and Chrysler dealer said the bolt isn't available. The Benz dealer quoted me about $1,100 for a SuperCharger Repair Kit which includes the Clutch/Pulley, Belt, nose of the Supercharger. The Chrysler dealer only list the Supercharger as a complete assembly for about $5000. No way to get just a bolt. I'll take the gamble over spending $1,100. If my I lose the bet, I'll just have to buy a used Supercharger...

So far so good. I've had it on there since June and traveled about 4,000 miles with no issues. I've driven 1500 miles to the Dragon and Back including heavy beating for most of the weekend. It's been to the track several tmes and probably has 25 1/4 passes on it and countless 6,250 RPM blasts on the street. I've checked it 4 times to make sure it is tight and the pulley is properly aligned and positioned. Only time will tell.

 

No, the OEM bolt has a hole in it, from the tip up through the head. You can hold it the bolt up to a light and look straight through it. I'm holding mine right now. Boy do I wish I had a camera...

What are the pics you posted, your OEM bolt??? Not at all like mine...

 

Believe that's his broken bolt and the replacement he used.

 

The one without a head is the broken OEM one. The other one is what I replaced it with

 

Crap I stepped on my self, Dummy Dummy. I gotta pull mine out and retorque it as I just unstacked my pullies and had used my impact to remove the bolt. Time to get the inch pound wrench out to torque it Just right before it all goes TINK.

Gotta see this bolt from a better perspective, pardon me. Woody

 

The torque is 22 ft-llbs right? Around there? Or was I completely off?...

And yeah Woody, the bolt is almost flexible, so when you 'break' it it actually doesn't break at first, it instead twists. And twists. So the strength of it is gone, twisted, but the bolt is still intact which could make someone think all is ok. One more turn and the final snap occurs!

Its actually a great design to make people not over-tighten it. Also, you'll notice the threads are located further down, this promotes to break point to be up towards the head, making it easier to pull out.

Hollow plus no threads towards the top = safe design for people like me.

 

SC_breakout_PIC.jpg

 

i am pretty sure it is somewhere between 14 and 17

 

# 55 will give you the bolt, but it will cost you $1,000 + at the dealer. That is the same diagram the Benz dealer showed me.

 

call, email, or PM Brandon of Code3Performance. He may have some of these bolts. This has happened a couple times (if i remember correctly) to members on mbworld

 

Brian, that is an EXCELLENT picture showing the missing Air Flow Sensor Gasket. You guys should ALL print or save this picture for later reference. The AF Sensor gasket is just two metal plates moulded into a rubber gasket that is .600" thick. It mounts the throttle body to the SC. The gasket can crack at the metal joints and then you have an air leak. Once it gets a crack it can/will grow until you have two pieces. DO NOT twist on the gasket when you are working on your throttle body or on your intake system. Thanks again Brian.

MikeR