It broke because the manifold warped and over-stretched the stud....which is also why it came right out with that wee extractor. The fact that it broke under tension means that there is no thread drag.
Broken exhaust stud removal
- Thread starter JHZR2
- Start date
JHZR2
Staff member
Maybe it was because the HF set is some cheaper high carbon steel, with more “give”?
Regarding the thread chasing, I have a no-name set I bought like new off FB Marketplace. It seems good enough. M8 chaser nut worked fine on old threads, but chasing the holes was harder.
Generally I could hand thread an old stud in, but I was unable to hand thread the chaser. I certainly don’t want to stretch out the holes.
I have a Lang tools set on order since that one seems to be the gold standard. But my question really becomes - how much do I really push it? If I can’t thread in the chaser, but I can thread the studs, is that good enough?
All but two studs came out easily, clean, dry, effectively looking like new. So I’m not sure there’s much to chase - seems the potential of damage is worse than doing nothing.
Maybe a diy chaser is the best bet?
I didn’t realize that most are carbide. The cheap ones I got said they’re a fortified high carbon steel. Usually I wouldn’t buy hf stuff like this, but maybe it’s better that I did! The extractor cracked when I tried to thread it out.
This is what I got:
https://www.harborfreight.com/screw...ce-63987.html?hftm_sc=3098&hftm_source=google
Fortunately there really was no corrosion on the studs that came out.
maybe??? I haven’t put a straightedge on it to check for warpage or “growth”. There was no practical thread on the female exposed hole. I couldn’t get that bushing I made to go in even 1/16 turn. Given that, wouldn’t the rest of the stud have fallen off and disappeared long ago if it were long broken due to wastage? It’s not like a 5 cyl diesel is the worlds most balanced engine.
When in doubt most of the time I will use a poor mans tap with some cutting fluid. Start it straight and just use a small 1/4 ratchet to drive it, if it comes to a stiff spot remove it use more cutting fluid and go again, not too much force but enough to thread it in. Make the tap with a 10.9 grade bolt.
I can only imagine the elation and relief you probably felt when that piece came right out. I would have been jumping up and down, running around the garage hooting and hollering and pouring beer over my head like I just won the world series. I HATE pulling heads. I just pull engines now. I was given a set of headers for my Sequoia and I thought great, the factory manifolds both have minor cracks and this will take care of that. After I crawled under and looked at all the nasty hardware holding the factory manifolds on I noped the hell right out of that idea. Those headers have been sitting under my workbench gathering dust for several years now and I doubt they will ever see an engine again.
Nice work on the extraction. Slow day at work yesterday and when I read the first post I let out an audible "Eeewww" just reading it. Broken exhaust studs on an installed engine are nightmare fuel for me.
Nice work on the extraction. Slow day at work yesterday and when I read the first post I let out an audible "Eeewww" just reading it. Broken exhaust studs on an installed engine are nightmare fuel for me.
If that bolt is now seated against the broken stud it won’t do much good to use a left handed bit. Now if you get a deep drill into the broken stud maybe then removing the bolt and begin with next larger size left hand bit could be successful. It could take a combination of an Ez out, penetrating oil, and heat around the bolt hole. One thing is for sure, a broken Ez out means the head is coming off.
You lucked out. At least it was not seized bad, or messed up threads.
JHZR2
Staff member
The point of the bolt was to act as a drill bit guide to get a reasonably straight hole in the stud.
I guess it was good that I used the cheap HF bit since it’s not carbide…
CleanSump
Site Donor 2026
You can use a file or a dremel to cut a slot in a grade 5 or 8 bolt to make a thread cleaner. You're not really cutting new threads, just scraping out the rust and crud.
JHZR2
Staff member
That’s why I was thinking to cut one from the oem studs that came out. Most all look clean and dry, like new.
AKA a poor mans tap. It is metric so a a 10.9 bolt is preferable.
JHZR2
Staff member
So I got back to working on my manifold, cleaning and prepping to re-stud and put it back together.
I have the Chinese chasers, the Lang chasers, and lots of OE studs that look pristine.
I actually cut slots into one to make the poor man chaser because, why not.
I have zero issue getting the OE stud in, but once cut it won’t go! I use a lot of ATF.
It does pick something up
It goes in about as far and feels about the same as the cheap Chinese chasers. The lang chaser and the OE bolt uncut go in about the same as well.
I’m deathly afraid of aluminum. And damaging the threads while blind on the head.
I’m only turning with my fingers… not even a wrench. Abundance of caution.
What should my plan be??
Thanks!
JHZR2
Staff member
Well, I did nine holes (one has a good OE stud that doesn’t want to come out so I’m not going to force it).
I used tapmagic fluid on my poor man tap.
A little sludgy residue, and I used a ratcheting wrench as gingerly as could be to help get it through some spots. Otherwise it was all by hand.
Next I’ll spray all holes with brake cleaner, blast everything with air, vacuum the exhaust ports, and thread in the studs with Nickel Antiseize.
I used tapmagic fluid on my poor man tap.
A little sludgy residue, and I used a ratcheting wrench as gingerly as could be to help get it through some spots. Otherwise it was all by hand.
Next I’ll spray all holes with brake cleaner, blast everything with air, vacuum the exhaust ports, and thread in the studs with Nickel Antiseize.
I think the angle of your cut in the bolt has made your thread chaser less effective and led to your jamming problems.
Because those “grooves” in your bolt have a shallow edge, you’re forcing a wedge into each thread, and when it encounters the debris, it wedges the debris deeper into the cylinder head/female threads.
I think what you need is a sharper angle, so that at 90° piece of thread encounters the debris and sweeps it out of the female threads.
Example below
Because those “grooves” in your bolt have a shallow edge, you’re forcing a wedge into each thread, and when it encounters the debris, it wedges the debris deeper into the cylinder head/female threads.
I think what you need is a sharper angle, so that at 90° piece of thread encounters the debris and sweeps it out of the female threads.
Example below
JHZR2
Staff member
What did you use to cut that?
In the past I tried an angle grinder and had no success. This time I used a 3” cut off disc in an air cutoff tool.
I’m thinking dremel?
After the first few threads every single one threaded in easily by hand. And when I blasted them clean no debris/coloration came out with the solvent, FWIW. I believe these are all quite clean inside.
But to make the right tools is a good endeavor. I’m not shaky, have a good vice, but getting the slots right is a challenge.
I thought a bit wider also allows more space to catch the debris. I was under impression that at 12 o’clock the angle should be a sharp 90, and at 10 o’clock it’s shallow, tapering to thread.
Been doing this since the early 70's or so. Can also use a small cut off wheel on a 90 degree grinder, depending on the bolt diameter.
JHZR2
Staff member
That’s what I did, 3” cut off wheel on a small air grinder. But it’s an M8 bolt so not much to work with. Hit it wrong and you’re done.
I feel like the air cutoff is still too big to have the control needed. Maybe it’s just me
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I use a Dremel, in fact I have to make one tonight for a brake line fitting that is not a standard tap size that I have. The things came out very tight so there is some rust on the female threads that need to be cleaned up. Standard rust belt fiasco.
JHZR2
Staff member
M10x1.0?
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