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I'm actually about to change my exhaust one of these upcoming weekends. I figure I may as well replace all the bolts/nuts with new stainless steel ones.

Anyone know the thread/dimensions? so I can go buy them before getting under the car.
I think they are M8 x about 3/4 in
I used lock washers- stainless bolts and nuts

Drilling works if you have a good right angle drill setup
 

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Installed Dream 1 today and sheared off 2 bolts from the header flange...Thanks to the technique listed I was able to get them out with no problems...Thanks
 

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In the process of replacing my clutch on my 07 Cayman S at 159k I snapped 4 of the six bolts. Heating the bolts worked flawlessly. I wasn't sure what was meant by a "plumbers torch" so I used it as an excuse to purchase a MAP torch (every major project is obligated to add to my tool collection). It heated the bolts up in about a minute each. I heated them up from the backside. The flexible hose made positioning the torch a breeze, but I suspect you could get at them with a torch that mounts on a tank as well.
 

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Same problem here but only broke off (4) of the manifold flange studs ((2) each side - exhaust side of the manifold). I wasnt too sure of myself about heating the studs and wasn't too keen on removing the manifolds so I tried a similar technique to the c-clap idea. I knew I didn't want to hammer on the manifold. I bought this tool at an auto parts store and thought it more substantial than a small c-clamp. The big issue for me was how does one push the broken stud out while leaving room behind the stud for it to move out? So I placed a large socket in the 'pocket' of the tool as shown in the pick and all broken studs pushed out with relative ease once the (2) spot welds holding each stud in where broken. I also included a photo of one of the broken studs that was pushed out. Pushing all 4 broken studs out took an hour but I was moving very slowly and carefully while the car was on jack stands.
 

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Snapped two studs on my passenger side earlier today while upgrading the exhaust... Even after multiple soak cycles and heating the bolts before trying to remove them.

So far no joy getting the studs out with the manifold on the car, tried some clamps, heat, hammering, but it's hard to get a good angle or clearance. Guess I'm pulling the manifold.

I noticed on the drivers side (which came off without any snapped bolts) two of the studs had already been replaced with bolts, must have been by the dealer as they were the only ones that worked on the car with the previous/original owner.

Wondering if any of the folks who posted above that had heat/press or hammer work for them were able to do it with the manifold still on the car?
 

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Hi pfbz,
I just replaced my exhaust on my '06 Cayman in January and broke four of the six exhaust flange studs in the process of removal.
I too PB blasted all of the hardware for several days before I even started, but I lost four of them anyhow.
I was able to heat up three of those with a propane torch and bang them out with the exhaust manifolds still on the car, but there was a fourth stud that I just couldn't get to pop out. it was the innermost stud on the passenger side and I could not get a good angle at the stud to bang on it.

I resigned myself that the exhaust manifold would need to come off the engine and I was dreading that it would be a difficult thing to do.
Not so. It was about a 15 minute job to unscrew and remove the two O2 sensors and unloosen/remove the six manifold bolts, and the manifold just dropped down and out.
Once the manifold was out, I took it over to my workbench, heated the broken stud and whacked it about three times and it popped out.
Had I known how easy it was to remove, I would not have heated and banged on the broken stud for 15-20 minutes, bashing my finger in the process, I would have just gone straight to removal of the manifold.
I guess what I'm saying is that if any of the studs prove difficult to remove with the manifold still on the engine, don't stress too much about it and just remove the manifold.
It took even less time to re-install the manifold taking care to not over-tighten the manifold bolts (17lb-ft, I believe).
Now, my Carnewal GT mufflers are on and sounding gooooood.
.
 

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I just had all six studs break on me. After drilling and heating with much failure I finally figured it out. First grind the broken stud flat so you could get a good whack at it with a punch, then heat the flange with a propane torch until cherry red. Literally took two hits with very little force to knock out the broken studs. Having the broken stud ground flat lets you direct the energy directly at it and made a huge difference. Had I known this I would have saved myself 3 hours drilling. Can't state enough how easy this is if you do it this way!
 

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I just had all six studs break on me. After drilling and heating with much failure I finally figured it out. First grind the broken stud flat so you could get a good whack at it with a punch, then heat the flange with a propane torch until cherry red. Literally took two hits with very little force to knock out the broken studs. Having the broken stud ground flat lets you direct the energy directly at it and made a huge difference. Had I known this I would have saved myself 3 hours drilling. Can't state enough how easy this is if you do it this way!
And did you do this with the manifolds removed or still on the car? As rackhenry mentioned above, getting access for a grinder, punch, hammer is pretty difficult with some of the studs.

My only fear of pulling the manifolds is that if a manifold bolt shears, then I'm sliding down the slippery slope on my *** at light speed.
 

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And did you do this with the manifolds removed or still on the car? As rackhenry mentioned above, getting access for a grinder, punch, hammer is pretty difficult with some of the studs.

My only fear of pulling the manifolds is that if a manifold bolt shears, then I'm sliding down the slippery slope on my *** at light speed.



I did this with the manifold on the car. Broken exhaust flange is nothing in the big picture, had I had to drive the car that way for the next race, then so be it. However had I jacked up my head as the car is 7 years old and spent most if its life in cold weather, I did not want to chance taking the manifold off and ruining my head.

I would say that getting access is a pain but I went around that and took my suspension off. That part was easy, but time consuming...

My thought though is this.... the head is aluminum and it is doubtful a manifold bolt with 17 Ft lbs of TQ in an aluminum head would be any problem.. but....It is really the big if, and I simply did not have the time to take that chance before next track day. I eventually am putting a header on so will report back here how it went.
 

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OK, as suggested, I

  • pulled the manifold
  • gassed the broken studs
  • hit 'em with a hammer, then a punch
  • and they popped right out.
Manifold bolts came out very easily, 02 Sensors loosened quite easily with a standard 22mm open wrench, no need for a special O2 socket. If you break an exhaust stud, just pull the manifold to pop the studs out if you can't get to them easily in the car (as suggested by many above).

I'll tell you the manifolds are *way* easier to remove than they are in a 996!! Easiest to remove exhaust manifold of any car or truck I've ever worked on! Brilliant access...

Tools of 'reconstruction':




Easiest to remove exhaust manifold of any car or truck I've ever worked on! Brilliant access...
 

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Eeek. I sure hope that I don't have to do this. But, if it ever happens, at least i have learned something.

The promise of a $300 or less stainless, cat-delete exhaust may very well tempt me in he future. Especially if @pfbz gets a HP boost from it.
 

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BTW, for those doing a stud replacement, don't use stainless bolts is the info I read in a few posts about stainless breaking under high heat.. ymmv... I used grade 10.9 zinc coated bolts.

Basically someone posted about the exhaust falling off when the stainless bolts could not stand the heat cycles... Honestly first I ever heard of it.
 

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BTW, for those doing a stud replacement, don't use stainless bolts is the info I read in a few posts about stainless breaking under high heat.. ymmv... I used grade 10.9 zinc coated bolts.

Basically someone posted about the exhaust falling off when the stainless bolts could not stand the heat cycles... Honestly first I ever heard of it.
I've not heard or read that before. All of the advice I've seen on multiple forums is to use stainless bolts/nuts.
What do the tuners and speed shops recommend and use?
I'd trust their experience.
 

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I haven't heard that before either... For that matter, high grade bolts (even non stainless) are more 'brittle', a trade off for their strength, so the argument might be made to use grade 8 instead of 10, etc.

But personally I'll continue to use stainless and high grade fasteners. Pretty much the only problem I've ever had with stainless fasteners is galling if they get driven in too quickly with a power tool.
 

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I haven't heard that before either... For that matter, high grade bolts (even non stainless) are more 'brittle', a trade off for their strength, so the argument might be made to use grade 8 instead of 10, etc.

But personally I'll continue to use stainless and high grade fasteners. Pretty much the only problem I've ever had with stainless fasteners is galling if they get driven in too quickly with a power tool.

I don't disagree with you on the stainless, however the article made me think... Just some food for thought, why does Porsche not use stainless fasteners anywhere on a full stainless exhaust? I can see a few potential reasons, sticking to the flange, actually having the studs snap was easier than having to strip a nut I would guess.. But overall are they saving money here, yes but is that the primary reason.. I don't know and if Porsche is willing to use cheap grade 5 studs then I seen no reason a grade 10 bolt would not work. This is a great article in pdf format..

http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf
 

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Hi all, trying to remove my OEM and install Carnewal now. not a single nut has come off without rounding out, so i used about 485 dremel cutoff wheels and cut (2) out of 3 off the passenger flange. i'm so sick of fiddling and having cutting wheel shrapnel flying i'm considering pulling the manifolds, but my question is-can you pull out all the manifold bolts, and wiggle the entire assembly out in one piece like that? seems liek so many bends to get out the back of the car. if so i think i'll do that, i haven't even touched the driver side yet and i've already got an easy 3 hrs into my passenger side and the last nut isn't even all the way cut off yet.
 
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