HELP - removing broken exhaust flange studs

I've got a 2006 Cayman S that I'm trying to swap exhuasts on. In the process of taking the old exhaust off, I managed to break one of the studs on the triangular flange. The stud that is currently broken is the outermost stud on the passenger side manifold. I've had this problem before and I drilled the studs out. However, this one is angled in such a way I can't seem to get my drill on it at a straight shot, so that's out. I've been using a torch to heat the stud head and try to hammer it out. So far it hasn't budged one bit. Can anyone give me detailed advice or tips on how to do this? I've searched and found that people were successful with this method, but I haven't been able to find detailed instructions. I'm also trying to avoid taking the manifold off the car. The bolts holding it on are rather rusty, and I'm not looking to break one of those, too. Just as a side note, if I do have to take the manifold off, I'll have to remove the oxygen sensors. Will spraying them down with PB Blaster damage them in any way? I've already called a dealer in case this gets too bad. But they are booked up and can't look at the car till Tuesday, so I've still got some time to get myself deeper into trouble. Thank you in advance, Mike

Yes, take the manifold off. It should be really easy. PB Blast, you should not even get close to the sensor. Also, may want to consider after market headers ... maybe less than a trip to a dealer. Who knows, they may sell you new OEM units.

some folks report that a c clamp and spacers can push the broken stud out, others use a dremel . the sensor should not need any p oil it should/may have anti sieze on the threads [dont get anything on the sensors end] if you snap a stud in the head you are in for a world of hurt and money

Same thing happened to me last weekend. All three bolts on the passenger side broke off. Had to take the header off and went through about 20 colbolt coated bits before we got them out. After about 12 hrs, I was finally able to start my car and hear my new exhaust . Good luck man!

the studs aren't just press-fitted into the header ... they're spot welded. drill/break those welds and the studs can be pushed out.

I found that drilling/ breaking those 3 tack welds didn't just do the trick. I ended up using a metal cutting dremel attachment and cutting the bolts off. I took away "slices" of the machined press bolt withe the circular metal cutting piece. I cut straight down into the piece so it took me about 22 "slices" to get rid of the bolt. On a side note, I don't think I would have called the dealer... I'm sure they're going to want to sell you a new catalytic converter for like $1.8k When you do get the bolt off with whichever method you choose, just go to Home Depot and get some stainless replacements. Mine are holding up fine after seeing rain, salt and winter. I had to replace two and it was a royal pain in the a$$. You'll get through it, just takes time and patience.

Hey everyone, Thanks for all the replies and follow ups. I managed to get the stud out this evening. I used a torch to heat the stud and tap it out with a screwdriver and hammer. Once I got the hang of it, this turned out to be much easier than drilling the studs out (as I had to do on my brother's Cayman when we changed his exhaust ). Also, I didn't find that my studs were spot welded into place. They were only pressed in. There are splined collars that the studs are pressed into that are spot welded into place, but you don't need to take those off to remove the studs. A couple tips for anyone else that has to do this: I jammed a piece of wood under the exhaust header. That let me hit harder and avoided the vibration and bouncing around that I was experiencing before. It helped me get better shots on the stud to knock it out. The stud needs to be REALLY hot for it to come out. I've never worked with a torch doing something like this before, so I was a little shy about applying too much heat. I had to get not only the head of the stud, but the flange, and the tail of the stud extending behind the flange red hot before it would come out. But, once I was brave enough, the stud slipped right out without much effort. Finally, I was having some trouble at first with the screwdriver slipping off the stud when I tried to hit it. I got a hacksaw and made a little groove into the tail of the stud. Then I used a flathead screwdriver to tap it out. Anyhow, I'm glad it's out without damaging anything else, or having to tow the car to a shop. And knowing what I know now, I think that if any of the other remaining studs were to break, I could get them out without nearly as much trouble. Mike

Wouldn't you want to heat the flange to make it expand & not the stud? That's what I do when I have a problem with an interference fit.

Diverdog, I thought the exact same thing, heat the collar, make it expand and slip the bolt right out. I tried that, but it wasn't working for me. I even went so far as to avoid the stud as well as I could and then use ice to try and cool it down while leaving the flange hot. None of that seemed to work, though, the stud wouldn't budge. Two things might be at work here. First, the stud and flange are pretty small and they are touching each other. So heating one invariably heats the other, and the difference in temperature between the two isn't enough to release the stud. The second thing is that heating all that metal up red hot might change the friction characteristics between the two surfaces so they will slide past one another easily. I could be totally wrong on the reasoning, but it worked well for me. Mike

the important thing it that it worked!

Holy thread revival batman...Christ just did this 40 minutes ago, glad it's replaceable and not welded in. About how long did your heat with a torch ( I assume you mean like a plumbers torch )method take? And on a side note the gator bite ramp method isn't working for my paws, what alternate jacking points besides those in the manual can you use to get jackstands under there. Thank god it's replaceable..

Westby, I heated the stud with a plumbers torch. As far as time, I don't know exactly, but it was more than I was feeling comfortable with at the time. The flange, collar, and stud were all cherry red and glowing. I heated from the engine side, and the tail of the stud (mine was sticking out) was glowing red hot. I might have had it on there for a 60-120 seconds. A couple other tips: I didn't know how much to heat them, so I tried multiple times, gradually heating it more and trying to pound the stud out. It might take more than one heat cycle to break the stud free. When you heat the stud, don't let it cool down. I started pounding on mine while it was still red hot from the torch. I'm not sure if that's the correct way, but it is what worked for me. Just don't bend the flange! As far as jacking points go, under the car there are two flat metal bars that go from in front of the wheel housings to behind the engine. They are angled from outside to inside the car as they go from front to back. Those spars have bolts that connect them to the car. Two of the bolts are fairly close together (there are four that you can see, and I think that the correct two are the two in the middle). Those bolts connect to the engine cradle. If you put the jack between those two bolts, you can lift the car where the engine cradle connects to it. Someone else might have a picture of it, but hopefully that description will let you locate them. Good luck with the studs, they are a real pain. Mike

When I changed my exhaust , I broke a few bolts. I used the c-clamp and a strategically place socket or two. No heat, no banging, no dremel (usually my favorite --get out of a tight jam tool). I just kept turning until it popped out. I replaced them w/ stainless bolts and nuts -- no problem. good luck,

Hello everyone, I'm new to participation in this forum but have lurked for a few months. I own a 2008 Boxster -S and have recently installed a Borla catback system. The OEM header flange nuts came off and went back on with no problems but I plan to replace them with stainless. Questions: 1) Does anyone know what torque is recommended to tighten these nuts? 2) Any experience using anti siege lubricant on these nuts? I do enjoy the sound of the unit but look forward to future discussion regarding a possible solution the drone issue. Jim

1. 17 ft-lbs is what others have quoted, though I can't find any official reference. 2. I think anti-seize lube is a good idea, especially if you are contemplating changing the exhaust yourself in the future. I did it on mine. If you do a Search for exhaust drone or similar, you will find several discussions on this topic. My conclusion (having participated in the discussion and exploration for possible solutions) is that drone is an unfortunate byproduct of many aftermarket exhausts. It is largely produced by the inherent, natural resonance of the exhaust system, which Porsche managed to tune out with the rather restrictive internal (muffler) baffling and plumbing. Member Plainsman has been exploring possible fixes to an aftermarket exhaust here: http://www.planet-9.com/cayman-boxs...oxster-modifications/50861-exhaust-drone-resonator-fix-design-construction.html

KS-CS, Do you have any experience with Catback systems with arms, similar to the Borla design, that attach to the top rear of the transaxle housing? I'm looking for advise as to how much torque should be applied to cap screws used to fasten these arms. I have experienced severe deformation of the "rubber" isolators used in this Borla setup using their recommended torques. Thanks for your help. TexasFlatSix

This old thread saved me yesterday. What should have been a 1 hour project turned into a 5 hour frustration. While swapping the exhaust , even with lube I snapped 4 of the 5 bolts. C clamps did not work, I actually broke a C clamp. Drilling did not work, I broke a bunch of expensive drill bits. All else fails... light it on fire and hit it with a hammer! - Worked like a charm! $25 plumbers torch for about 2 minutes until it starts to turn red. Smack it with a punch & a hammer and they pop right out. Replace with stainless bolts and good to go.

I went to install my exhaust last week and got discouraged very quickly. Got the rear on stands, soaked the bolts, got one nut off, the second rounded on my first wrench turn. I was very surprised at how rusty the hardware was for the exhaust , my 964 had better exhaust hardware. Called my friend who is a Porsche factory master tech, he said "those studs usually break off". So the car goes to him on Tuesday, and I get to drive a new Boxster for the day.

Yup. I had several break off with barely any force, even after letting the lube soak in. I was stressing out a bit until I found this thread. Now that I know the blow torch technique, and having experienced getting those factory bolts out. Not a big deal. Enjoy the new car for a day! I had my strut bearings replaced under warranty and they loaned me a full loaded 981 Boxster S for 2 days. I got absolutely no work done, and I returned the car with 600 miles more than they gave it to me with. :drivingskid:

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

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

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.

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.

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?

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. .

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.

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...

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.

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.