Are you using high quality drill bits? Find your local industrial diamond drilling supply and they'll sell you some high quality cobalt bits that'll cruise right through that stud. The big box stores, Sears and most hardware stores carry low quality drill bits that aren't worth using for such a project. Just because it says cobalt doesn't make it a good bit! Always use low speed while drilling metal and lubricate with drill lubricant. Keep the drill bit cool, let the bit do the work. A high quality bit will cut right through a tap also.

 

I'll drop down to the local machine supply shop and try some of their cobalt bits (bought a good extractor there yesterday, have already lived the nightmare of a broken reverse thread drill bit type extractor last spring).

 

I came across this link while searching broken bolts solutions. I've never used it, but it may do the trick? Anybody else ever used it?
Removing Broken Exhaust Manifold Bolts with Threads Still Intact | BrokenBolt.com

 

well all is done, one less modular with a leaking manifold , thanks to all who gave advice. The tool in BFTUFF's post post looks hand for making sure you whole is straight and centered, but looks "bulky" for under hood use (concerned about the thickness of the bushings taking up precious space in tight areas like the miserable #5), i would love to hear from anyone who has tried it as well.

Thanks again to all for the useful tips

EDIT: forgot the LOL at the drill in the broken bolt demo vid, Try getting that in your engine compartment

 

 

That's what this is for:

 

Almost there.

Where can I find a tool for inserting and tightening the exhaust flange studs into the manifold?

... nevermind - used 2 nuts back to back to drive the stud into the manifold.

 

Put some of this on the studs entire thread surface before torquing them. High temp never seize. Stops electrolysis/corrosion and allows future removal. Works great, I've used it for years.

Loctite Copper Anti-Seize 37533 - SummitRacing.com

 

Using Permatex high temp anti-seize everywhere.

Another thought ... pretty certain this is the last time I'll be messing with the exhaust on this engine. It's 16 years old and has 320K on it. Once I get another 16 years & 320K I'll probably consider something newer

But I agree, if you do a job may as well do it right.

 

Yes sir, that's right!

 

Those right angle drills a f*&^ing heaven, but sometimes to expensive for the DIY'r to pick up in the middle of the job (like me, I am in the "dead season" between snowplowing and landscaping, so I figured I had the time to do it). Most big box stores carry a right angle chuck attachment similar to
it is what i used, it is big and awkward to use, but it did get the job done for 20$ instead of 90-200$ for the real deal. Just thought I would through that out there in case anyone else ends up in that situation.