Broke Exhaust Manifold bolts

Dustincoc · Jun 18, 2013

I managed to snap off all 6 exhaust manifold to head bolts on the head last night. Anyone know of an easy way to get them out with the head on the engine. One snapped off just under the head of the bolt and the rest are flush with the flange on the head. All this just to drill out the manifold to downpipe bolts which were broken off when I got the truck.

I think I'm going to reinstall it with stainless studs if I can find any.

RonD · Jun 18, 2013

I have had good luck with reverse drill bits, you may need a 90deg drill to get to all(any) of them.

Reverse drill bit cuts running counter-clockwise, so vibration of drilling can loosen the bolt while drilling, and it just unscrews.
I would say that happens 80% of the time, but if it doesn't then you still have the hole to use an "easy out", this is a hard steel cone with threads that go into the drilled hole and grips the bolt from the inside, then....hopefully it can be unscrewed.

Bolt extractors can be used where you have part of the bolt to grip.
If you have a torch you can try heating up the head, NOT the bolt, to get the metal around the bolt to expand a bit and loosen it's grip.

Penetrating oil is always good

And just for future reference, my local muffler shop charges me $20-$50 to loosen and replace(as needed) all exhaust bolts on the engine I will be working on, takes them maybe an hour at most, I drop it off and then pick it up and take it home to do the engine work, worth it to me to not have to hassle with rusted exhaust bolts.
Good deal for me and for them.

Not sure you will have the clearance to use studs.

Dustincoc · Jun 19, 2013

I've got some easy outs around, never had much luck with them. I've got them sprayed down with penetrating oil. I'll need to pick up a set of reverse drillbit and a right angle drill adapter.

The trucks not on the road so driving it to a shop was not possible. This is one of the many needed repairs to get it roadworthy again.

I expect clearance for studs won't be a problem. I don't see them taking up any more room than stock. I've got the entire front end body removed except the inner fenders and core support although the core support will be being removed as I progress.

adsm08 · Jun 19, 2013

Do not use stainless bolts. Stainless will strip out the head if they have to be removed at any point in the future. Use regular bolts with copious amounts of anti-seize.

shane96ranger · Jun 19, 2013

First off, sorry for the semi-threadjack. But I have to share.

I know I am going to have to go through this drama in the future on my F150, so I looked up some tricks to the bolts out ---- but prior to breaking them. I stumbled onto a Corvette forum, and I am just in AWE over this guys comments. Some advice was given to get a 13mm socket and pound it onto head, then utilize a breaker bar to break it loose. The OP replied, not once, but twice with:

I would like to try tapping a 13mm socket on each of the bolts. Should I try getting a socket at a junk yard? Where would I be able to buy 2 13mm sockets?

Well, the bolt is still stuck and I may need to find 2 13 mm sockets. (1 for each bolt.) Do you think a junkyard is the best place to find them? Or where I can I buy just 1 socket?

I am still up for any other creative ideas?

Holy hell.... just.... holy hell.

See for yourself: http://forums.corvetteforum.com/c3-tech-performance/239653-exhaust-manifold-bolt-stuck-advice.html

adsm08 · Jun 19, 2013

I was going to sign up and comment on his mental faculties, but then I saw the thread was 11 years old.

shane96ranger · Jun 19, 2013

adsm08 said:
I was going to sign up and comment on his mental faculties, but then I saw the thread was 11 years old.

Same here.

I'd hate to own a car after that guy.

RonD · Jun 19, 2013

So where did he finally get those 2 13mm sockets?

Don't leave me hanging........

adsm08 · Jun 19, 2013

He didn't. His brother took it to a local shop that ground the heads off to 1/2".

I know, I don't quite buy it either.

shane96ranger · Jun 19, 2013

I wonder if the exhaust shop used two 1/2" sockets?

RustedRanger · Jun 20, 2013

+1 on not using stainless bolts....but for a different reason I heard about. They are "softer" and can snap off easier. A former linesman told me they tried stainless bolts on metal towers but the would snap off when they tried to remove them. Just use anti seize.....I wish everyone did

Dustincoc · Jun 21, 2013

adsm08 said:
Do not use stainless bolts. Stainless will strip out the head if they have to be removed at any point in the future. Use regular bolts with copious amounts of anti-seize.

The plan was to use stainless studs and nuts instead of bolts. That way the studs would never need to be removed from the head, just the nuts from the studs. The fct that I pln on removing the manifold again is the reason for using the stainless fasteners. With the heat the manifold sees, any non stainless steel will rust.

RustedRanger said:
+1 on not using stainless bolts....but for a different reason I heard about. They are "softer" and can snap off easier. A former linesman told me they tried stainless bolts on metal towers but the would snap off when they tried to remove them. Just use anti seize.....I wish everyone did

Stainless is actually harder than regular steel and therefore more brittle, hence the snapping off. A "softer" metal would twist before it snaps. I looked into the comparative hardness of stainless last fall when I was planning a project using stainless nails. The manifold bolts are what I'd consider a non-critical connector, meaning there failure wouldn't destroy anything else. That is why I'm not too concerned about the added brittleness.

I use plenty of anti seize. We have a gallon can around we use on everything. I do somewhat doubt its effectiveness though since bolts I've used it on are just as hard to get apart as those without.

snoranger · Jun 21, 2013

Actually... an 18-8 (304) stainless fastener can be very similar in tensile and yield strength to a grade 5 fastener, depending on the exact mix found in the material. Its commonly lower though.

A SS fastener can range in hardness from about b95-c30 (rockwell scale) where as a grade 5 bolt is in the c25-c35 range. Again... Its commonly on the lower side of the scale.

What I'm trying to say is...
Stainless bolts are usually a little weaker and softer then grade 5. Thats why they break.

Dustincoc · Jun 23, 2013

I got one out this morning. It might be a 1/32 or 1/64 off of where it was. I ended up drilling it and running a tap in the hole to chase the threads, However, I feel a little ridge that sticks up on about half the hole.

I'm now running into a problem caused by my last attempt at getting them out. I found a lot of references to welding a nut onto the bolt fragment and the heat from the weld as well as now having a surface to grab onto being a foolproof method. I tried it on 3 different bolts and couldn't get a deep enough penetration into the bolt piece so the nuts kept twisting off. The welder did heat the metal up enough to harden it though so not the drillnit can't bit into the bolt to drill it out.

Broke Exhaust Manifold bolts

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