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Discussion Starter · #1 ·
I spend some time uninstalling the OEM cat back and in the process 3 out of 4 studs that connect the catalytic converter to the cat back have snapped.

Let's not get into the whys as it pointless at this point, but ofter a few hours heating and tapping the broken studs came out. Now I'm left with the hard task to find replacements. These pressure fitted studs are similar if not the same as to wheel studs. The problem is the size. The smallest wheel studs that I found are M10. The size that I need is either M6 or M8. Does anyone know where to source them?

I've tried HD, VIP, Auto Parts with mo luck. The Porsche dealer says that I need normal bolts and nuts at this point short of getting new catalytic converters.

Any help would be greatly appreciated.
 

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I agree with the idea of just using bolts. There is a video online of a UK guy who ran into a similar problem with the snapped studs. In this case being a purist is just not practical.
 

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Discussion Starter · #4 ·
I agree with the idea of just using bolts. There is a video online of a UK guy who ran into a similar problem with the snapped studs. In this case being a purist is just not practical.
Agree. I installed SS bolts and nuts. I only found imperials 5/16 1 1/2. Can still work on them with 13mm wrenches to it's a pretty good fit.


BTW the Fabspeed Racecup is nuts!!!
 

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Despite soaking days in advance with the best penetrate on the planet (Yield), snapped 5/6 of the little @#&#%s!
Well the Soul cat-back I chose ('06 987.1 CS) supplied stainless nuts/bolts in the hardware bag. At first, thought they were extras but Soul had some forethought on this old of a car. Did use a spot of copper on the gaskets and all went well. No leaks, movement or rattles after about 2 months of DD service. Unfortunately shes partially been put to bed due to the pending Adirondack winters I endure. Soul stuff is really excellent quality btw.
Good luck!
 
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Despite soaking days in advance with the best penetrate on the planet (Yield), snapped 5/6 of the little @#&#%s!
Well the Soul cat-back I chose ('06 987.1 CS) supplied stainless nuts/bolts in the hardware bag. At first, thought they were extras but Soul had some forethought on this old of a car. Did use a spot of copper on the gaskets and all went well. No leaks, movement or rattles after about 2 months of DD service. Unfortunately shes partially been put to bed due to the pending Adirondack winters I endure. Soul stuff is really excellent quality btw.
Good luck!
Thanks for the kind words but sorry to hear you had to put her away :( And yes, unfortunately snapping the studs is to be expected on these cars, we see it all the time even on newer cars as well. We opt to replace with a nice quality stainless nut/bolt combination as we have not been able to find the studs either.

OP, shoot me a PM if you need some hardware and I will pack some up and get it shipped out if I hear from you before 3:00 PM today. It'll be on the house, all I need is your shipping address.

- Evan
 

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A mechanic told me that the reason car manufacturers use plain metal bolts in exhaust applications is that unlike stainless steel they retain their strength under high heat. Is there truth to that and of so, maybe going with stainless bolts is not the best solution?
 

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Discussion Starter · #8 ·
A mechanic told me that the reason car manufacturers use plain metal bolts in exhaust applications is that unlike stainless steel they retain their strength under high heat. Is there truth to that and of so, maybe going with stainless bolts is not the best solution?
Time will tell... But Porsche replacement studs are not SS. They are some heat resistant something for a fair price of $8 and change each! I picked up HD SS imperial studs and never looked back.

Evan, thanks for the offer, but I'm all set now...
 

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A mechanic told me that the reason car manufacturers use plain metal bolts in exhaust applications is that unlike stainless steel they retain their strength under high heat. Is there truth to that and of so, maybe going with stainless bolts is not the best solution?
It is true that SS does not have the tensile strength of steel. I've snapped-off enough SS screws (on my boat) to know. I've also snapped SS bolts while removing them. Because of this I can understand why the didn't originally use SS studs. But once you've replaced the steel studs with SS bolts/nuts, it would be easy to insert a replacement if it happens. I doubt that this application requires tremendous strength and 3 bolts per flange is plenty to handle it. Just be careful and don't torque them as much.
 

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It is true that SS does not have the tensile strength of steel. I've snapped-off enough SS screws (on my boat) to know. I've also snapped SS bolts while removing them. Because of this I can understand why the didn't originally use SS studs. But once you've replaced the steel studs with SS bolts/nuts, it would be easy to insert a replacement if it happens. I doubt that this application requires tremendous strength and 3 bolts per flange is plenty to handle it. Just be careful and don't torque them as much.
Agree with what you said except on 981's they use 2 bolts per flange. Cost savings I guess!
 

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Apparently the original splined bolts aren't available

WM 261019 REMOVING AND INSTALLING EXHAUST MANIFOLD WITH CATALYTICCONVERTER (ALL MODELS) > REMOVING EXHAUST MANIFOLD WITH CATALYTICCONVERTER > REPAIR SOLUTION: REPLACING THREADED BOLTS ON TWO-HOLEFLANGE

1. Tap out damaged threaded bolts on the exhaust manifold using a hammer.Use M8 x 30 screw (Part No. 900.075.365.02) instead of the threaded bolt.
 

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That's correct Snips, if you go to your Porsche dealer and ask for the studs they will sell you grade 8 bolts. All I did was purchase some grade 8 bolts, washers, lock split ring washers and nuts. Worked like a charm. Just pound out the studs and replace, make sure to replace your gaskets as well.
 
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