When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I thought that since this has happened to me - it could happen to others. I have a 2016 991 GT3.
I removed my center muffler (CM) a couple of years ago and due to over torquing at the factory I broke one of the fasteners and stud when removing the CM. I thought the only eventual solution in going back to stock in the future was a new or used muffler. My conclusion came from researching the 991 CM parts catalog and finding nothing to help. Well, I found a that there is a part 997-111-727-90 that is a replacement stud. It simply screws into the CM. While some work is involved to remove the broken stud from both the CM and the fastener, the part cost less than $6. A few simple tools should provide the anticipated restoration.
Since I see so many folks seeking CM's, my feeling is this has happened to others and want to share to keep folks from throwing hard earned $$$ away.
What do you think would be the best way to get the broken studs out? An extractor bit? I have 2 studs that are broken. Thanks for the heads up and part number
What do you think would be the best way to get the broken studs out? An extractor bit? I have 2 studs that are broken. Thanks for the heads up and part number
My planned approach is as follows:
Apply heat to the broken stud on the muffler, assuming there is enough left to grip with a vice grip, which I have.
After red hot, apply a simple candle wax to the stud, it will retract to the threads.
Use the vice to turn it out.
Should that not be your case, then:
drill and use an extractor, however before extracting use the steps above.
From the looks of the part, it should not be a big deal. Let me caution you, there are not any left showing in the US, so it may take a month to obtain from Germany, unless your willing to pay a $20 shipping charge for a $5.95 part.
What do you think would be the best way to get the broken studs out? An extractor bit? I have 2 studs that are broken. Thanks for the heads up and part number
I also snapped two studs on my 2018 GT3 OEM CM when removing it to replace with JCR's Ti CM. Many thanks for this solution as i know its a very common problem...Why should be such an issue..?
I have the same issue with a 2018 GT3 CM, let us know if your planned approach works....Thanks
I am not planning on going back to stock soon, so I will probably tackle this project in a few months. Will post the results - should be fairly easy to repair.
I finally got around to repairing my center muffler broken stud using part # 997-111-727-90 that is a replacement stud.. My planned approach did not work and I had to drill out the broken stud and tap new treads. If anyone is planning on this as a DIY, use a 7mm drill bit to drill out the broken stud. Be sure to use cutting oil and start with a smaller bit and progress to the final 7 mm bit, then tap it using a M8 1.25 pitch tap. Finished product is shown below:
Last edited by 991carreradriver; 09-08-2020 at 02:25 PM.
I finally got around to repairing my center muffler broken stud using part # 997-111-727-90 that is a replacement stud.. My planned approach did not work and I had to drill out the broken stud and tap new treads. If anyone is planning on this as a DIY, use a 7mm drill bit to drill out the broken stud. Be sure to use cutting oil and start with a smaller bit and progress to the final 7 mm bit, then tap it using a M8 1.25 pitch tap. Finished product is shown below:
Thank you for posting this, have 1 broken stud following removal of mine, enough left to get the nut back on but likely not enough to ensure it will stay put!
What do you think would be the best way to get the broken studs out? An extractor bit? I have 2 studs that are broken. Thanks for the heads up and part number
What is the best way to avoid breaking the stud off - perhaps use a thread lubricant before attempting removal?
What is the best way to avoid breaking the stud off - perhaps use a thread lubricant before attempting removal?
Very slowly. When removing or tightening the bolts I noticed they get very hot. So I do one full turn on ratchet then move to another bolt. That way they don’t over heat.
Usually you tighten a little before you loosen to break the initial rust. Then combination of loosen and tighten the nut until it’s off. Lots of penetrating oil along the way too.
Very slowly. When removing or tightening the bolts I noticed they get very hot. So I do one full turn on ratchet then move to another bolt. That way they don’t over heat.
Originally Posted by CT944
Usually you tighten a little before you loosen to break the initial rust. Then combination of loosen and tighten the nut until it’s off. Lots of penetrating oil along the way too.
Yes they get very hot taking them off for sure (no rust was on mine but still loosened - tightened - loosened, also an odd angle for the lower rear posts causing the socket to torque on the stud a bit if you don't have a lift. I did both of these maneuvers and managed to only break 1 stud, fortunately it snapped off toward the end and there is enough stud remaining that with some loctite could easily put that nut back on if/when I put the stocker back on. Regardless I still bought a couple of the replacement studs and going to see if the local blacksmith shop can just replace the thing.I think my snapped bolt is due to the bit of an angle that even with a very long extension there was torque applied to the stud (should have just gone to hardware store and bought a universal articulating adapter)
03-30-2019, 07:08 PM
Center Muffler - Broken Stud
