Studs broke on Exhaust Flange

First post here so apologies if this has already been covered. My 2003 Toyota Tacoma decided to sound like a monster truck the other day. The pipe near the flange on the rear catalytic converter rusted off and broke off. Decided to replace muffler, rear cat and front cat. Got the O2 sensors off, start working on bolts that hold the front cat and exhaust manifold together and boom... bolt came off but snapped the threaded stud. Go to work on the second bolt... same thing snapped the thread. Third one I was able to get off. How the heck am I suppose to get the broken studs off the flange? I saw some guy online torch them and wax them, then vice grip. Any other ideas?


Success! But there were casualties...


Dangit! Busted two of the three studs

 

Cut them flush then dril them out and just replace them with a nut and bolt

 

Grind the two studs flush, drill out, then either replace w/ bolt & nut or tap with next thread size up.

Had the same issue, ended up drilling out and using bolt & nut.

 

Do not cut them flush!!!... they’re stainless., you’ll be snapping drill bits and then Your in a deeper hole than when you started. You have more than enough stud to grab with some vice grips. Soak them overnight in Aerokroil Heat them up and back those puppies out. You can also double nut it and then heat it up and try getting them out like that.

 

There’s so many factors in this... do you have a lift? If so then it’s a lot easier if you have no other choice but to drill them because they welded themselves in there over the years. I replaced my headers all the way back to my exhaust and I first tried backing out those bolts and it wadnt hattinin so I cut it off with a sawzall.
I’ve worked in the engineering dept on ships for years. I’ve had my share of drilling out bolts. If I have any of the stud still left I will give it all I’ve got before I have to drill them out.

 

No lift... gonna take it to the mech. I'm a noob. In way over my head. Lesson learned...

 

Ok to drive it? Mech is two miles down the road

 

if you can thread 2 nuts on them you CAN get them out. If you cant get 2 nuts on them can you get 1 and 1/2. If you have a oxy-acetalene torch or access to one it would be easier... you are going to heat the flange and the stud up, the stud until it just starts to turn red orange and let it cool. The differnt materials, cast iron and stainless steel expand at different rates. heating the stud to organe breaks the hold that the threads have on the stud. I let it cool then take a propane torch and heat the stud again just until the parafin wax melts. If you use WD-40 or PB Blaster you *might* have the following issues. As the stud is being extracted the heat that is generated will evaporate off the lubricant just when you need it and that is why you here people say I used a lubricant but I still broke the stud. Using parafin wax the heat melts the wax and it flows. When you stop it solidifies again until the next rotation. You are lubing it as you are taking it out which is what you want. If you cant get 2 full thickness nuts on it grind one down to 1/2 thicnkess. put that fullthickness one on first then use the 1/2 thickness one as the blocker/locker and use you wrench on the upper one to take the stud out.

If you cant get nuts on it, you could try heating it as above and buy a stud extractor. Snap on, Mac, Matco all sell fine stud extractors sets and if there is enough of the stud sticking out they will work... these kits arnt cheap.

if all of the above fail you are going to have to pull the manifold and drill it out... this might be a machine shop job depending on your availible tooling, like mentioned before, this is stainless steel and is very hard. That is when you have to grind it flat, center punch it IN THE CENTER, and use a titanium coated bit and drill down the center all the way through. Drilling all the way through allows for the stud to shrink just a little and allows for an easier extraction. If it still doesnt want to come out, very, very rare, you use the next size bit until you get it too where you can peel the threads of the stud off the manifold.

 

Thanks for the response. I'm going to soak it in Aerokroil overnight, then see if I can get two nuts on it. If not, 1 and 1/2.

 

What about a local exhaust shop just cutting it off and welding a new flange on... The right guy won’t charge you that much.

 

I second the vice grip and hosing it down with PB Blaster.
That worked for me on a terrible broken rusted to hell stud on my lower ball joint.
I'll post of pic of how bad it was if it would encourage you.

 

Soak in Kroil or a mixture of acetone and ATF 50/50, tig weld a nut to the stud and ususlly it will back out. Love taps with a hammer don't hurt either. Bang, heat, soak.

 

This is great advice. I've successfully drilled out or removed quite a few broken bolts/studs in the past 20 years and I think the above explanation is better than I've ever read before. It provides more detail than many folks probably want to absorb but, but still great.

 

Quick question. Are these captive bolts on the other side of the nut where it’s circled in red?

Edit: It is not.

 

On my 2000 they are just bolts and nuts With walker Exhaust products

 

I got all of them off but one that needed grinding. I’m replacing them anyway.