'05 Pacifica broke exhaust studs
 

Hello,

I'm replacing the cat and front muffler, and managed to snap off two of the three studs that bolt the cat to the header pipe. In spite of spraying several times with PB Blaster and letting it soak, as well as getting them cherry red with a torch, they did not break loose and broke off. I've now pulled the cat and muffler out and now I'm trying to figure out what to do. I've been looking around online and I see that some studs thread out, with a lot of heat and heavy duty gripping pliers, but I can't find anything on this particular model. Do they thread out with heat and muscle, or are they pressed in somehow? Do they need drilled out and tapped? I'm looking for ideas... and hoping I don't have to pull the header out to fix it.

Thanks

Look at the base of the broken stud. If the threads disappear into the header, then it's threaded in. If the threads stop before they get to the header, then it's pressed in, If the stud broke off flush with the header, you're going to have to drill it out no matter what. If it left you a protrusion, and if it's threaded in, you might be able to grind it square and then use an inverted socket of the right size to get it to move. Keep the PB Blaster handy. Without a load on it, the only thing preventing it from moving will be 16 years of corrosion. PB Blaster and some percussive persuasion can help with that.

Thanks for your reply. They did not break off flush, there's about 1/4" sticking out. I've attached images of the header I found online. They look threaded in. If they're threaded in, what would keep them in from turning out with the nut in the first place? High temp locktite? The ends of the studs have a small hex head on the end of them.

https://www.moparpartsinc.com/images...909AB_0003.jpg
https://www.moparpartsinc.com/images...909AB_0002.jpg

Actual photos of the header tell a different story I guess. Is it possible they are threaded on both ends with an unthreaded portion in between? Something like this:
https://cdn.shopify.com/s/files/1/00...g?v=1540834243
https://cimg5.ibsrv.net/gimg/www.chr...26ba15f4df.jpg
https://cimg7.ibsrv.net/gimg/www.chr...e3d4104cdd.jpg
https://cimg3.ibsrv.net/gimg/www.chr...7c7fb94a9f.jpg
https://cimg4.ibsrv.net/gimg/www.chr...3e1c0fe8d8.jpg

To follow up, I ended up removing the manifold to work on it, and broke two of the three bolts off in the crossover junction. I worked on it for hours with my drill press and hand drill, and couldn't get them drilled out right. I burned up all my drill bits trying to get this done, and gave up and went searching for a good used one. I had a couple leads at salvage yards but when they removed them they also broke off bolts. I ended up finding one on eBay for $50 that was already removed and looked good. It should be here later today.

I did find that the studs are threaded in and I'm guessing they use some serious locktite type stuff that won't release until you use a drill bit almost the same size as the hole and cut near the threads. This job is a major pain in the rear. I've replaced engines with less headaches.