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Hi,
Iīm changing heads on my 77 L48 vette. I have prepared pair of renewed heads, and need to remove old heads from car. I tried to remove exhaust manifolds today, I unscrewed 5 bolts, but the last one in center I broked under his head. Iīm not able to remove the manifold . I can turn manifold up and down on that broken bolt, It is separated from head, but it is not possible to pull it out. Is there any trick for it? I need to remove manifold to uncover head bolds. There is no space to drill it out. I tried to brush it with dremel tool and diamond ball on it, but that bold is soooo hard...
Please help
There probably a flare on the bolt caused by the head breaking off. The fact that the manifold can be swiveled on the bolt is in your favor. The problem is that the bolt is much harder than the cast iron manifold, so if you try to "walk" the manifold off the bolt you will have to drag that flare all the way thru the manifold bore, enlarging the bore as you progress. I think it boils down to what you want to salvage. Grinding some of the material from the bolt area would remove the flare, but ruin the manifold. Forcing (prying) the manifold away from the head about 1/8 inch and using a saws-all to cut the bolt could damage either the head or the manifold-or both. I would continue to try to rock the manifold as a helper pries the two pieces apart. Wear some leather gloves-this is going to be a knuckle buster.
Drill out the center of the bolt to weaken it. you should then be able to get the manifold off. Use a punch and center the drift mark. then start with a small drill and keep enlarging the hole until you think you are close to the manifold - then the bolt will collapse as you pull the manifold off.
IT'S a PIA but a right angle drill will make it easier.
No room to get a drill in there. Maybe a right-angle die grinder, though. Or get a harder burr tool for the Dremel. As mentioned, remove material just from the bolt. Start as near to the 'flare' as possible, without getting into the manifold. You should then generate a circular groove just inside the flare. That will give the flare room to bend inward as you pry the manifold over it.
Once you get it off, shoot penetrant on the bolt and let sit for a day or two (continuing to put penetrant on at some intervals). You don't want it to break again in the head!! You may have to grind some flats on that shank, if you can't remove it with Channel-Locs.
No room to get a drill in there. Maybe a right-angle die grinder, though. Or get a harder burr tool for the Dremel. As mentioned, remove material just from the bolt. Start as near to the 'flare' as possible, without getting into the manifold. You should then generate a circular groove just inside the flare. That will give the flare room to bend inward as you pry the manifold over it.
Once you get it off, shoot penetrant on the bolt and let sit for a day or two (continuing to put penetrant on at some intervals). You don't want it to break again in the head!! You may have to grind some flats on that shank, if you can't remove it with Channel-Locs.
Is it possible to pull the head off and the manifold as 1 unit if you can swivel the manifold enough to get to all the head bolts ??
I would soak the bolt with 50/50 acetone/automatic trans fluid and then tap the bolt many times. Acetone/AFT is a great penetrant and the tapping helps break the corrosion joint and get the penetrant in. They also make a "freeze off' which you spray for 20 or 30 sec which chills the joint. You might have to do this treatment for several days in a row.
yes you can drill the bolts, I have done it. See the pictures. On a C3 you can get right in with a right Angle drill, you may have to cut the drill bit if you don't have short ones.
You can also drill through the inner fender well and get a long bit into it, as you have to do with most foreign cars.
Grinding on the manifold into the bolt will mess up the manifold.
I use Milwaukee tools and the M12 right angle works well. I have an air powered drill - right angle that was for tight spots - worked well also.
Is it possible to pull the head off and the manifold as 1 unit if you can swivel the manifold enough to get to all the head bolts ??
Lots of really good suggestions, but if you can, remove as one unit both head and manifold as suggested by A88, then once removed it will be easier to separate them. Really like that right angle drill. Handy. Have to get one of those. Good luck.
I find myself using the M12 right Angle drill more than any other tool. It has a great low speed for removing screws and a power setting which helps not strip them when putting screws in.
The M12 system works great. The other half loves the heated JACKET when doing yard work. It uses M12 battery. HACKSAW for trimming shrubs/ small trees - cuts pipe easy also. I just sheet rocked the garage at the other house with the M12 impact gun - no power for a screw gun and to lazy to go and buy a 50' extension cord.
I've completed the set and find all of the tools extremely useful for most applications.
The M18 series tools are large and much more powerful but don't fit as easy into tight car spaces.
I find myself using the M12 more than the M18. Except for taking off lug nuts..
got a sawzall? use a long metal cutting blade and slice the bolt off between head and manifold. you could try a hacksaw blade with a plastic handle but they tend to be tedious and bend/break a lot, but can be done.
If you just cut off the shank behind the manifold, then you just have the same problem with the head. See if you can remove the manifold first. Then you will have the bolt shank to work with for removal.
Many thanks to all. Right angle driller looks like best method for me. It is not possible to swivel manifold to remove head bolts , they are direcly under manifold too, there is no space. I will take some pneumatic right angle driller and will try to drill out it during weekend. Thanks to all , I was really devastated after I broked that bolt, I thinked how I will grind it with angular grinder and will totally destroy manifold:-)
Greetings from Prague, Czech rep. !
If you just cut off the shank behind the manifold, then you just have the same problem with the head. See if you can remove the manifold first. Then you will have the bolt shank to work with for removal.
He said in the first thread he's got another set he is putting on, so that isn't a huge issue. also once the head's off, you can weld on a nut and spin it out pretty easily.
OP, be careful drilling/grinding so you don't wreck the exhaust manifold, unless you've procured a spare set of those too. not a bad idea to replace the exhaust pipe studs and use brass nuts (or go stainless) while you've got it out.
Google "Easy Out". I'm a Machinist this is not difficult you can do it.
I'm sure there is a great youtube to detail how it works someplace on the interweb. If not you can message me I would be glad to walk you through it.
Use a high spiral type stubby Nitrated Cobalt drill bit at around 500RPM. It's important you use this type drill! Lowes or the like stocks them.
Choose the correct size easy out. There will be a guide matching the bolt diameter to drill dia to easy out.
You drill into the center of the bolt as deeply as you can.
Insert the easy out tool into the hole then lightly tap it with a hammer to lock in place. Use a tap handle or if you don't have that use a open end wrench that fits the easy out.
tough to get a drill in there with the manifold on and get past it into the threads. likely that would just weaken it and snap it off flush...once the head is out and off the motor, the ez out may work...
I worked on it last weekend. I drilled it with angle attachment on driller with small cobalt drill bit, and grinded it with diamond ball on dremel tool. Continuously sprayed with rust loosener and little bit hammered. Liquid rust flow out as I sprayed it. Rest of broken bolt now turning up and down with exhaust manifold, but still not possible to pull it out. I taked photos below on sunday evening, when I ended work on car, and I see that trest of bolt is broken inside. I hope I will remove it next weekend finally. I removed manifold on opposite side too, I have done it in 20 minutes wihout any problem :-)
You're moving in the right direction! Just keep drilling it out and slowly move up in drill sizes until the bit is almost the same size as the bolt shank.
Do not insert anything in the hole you're drilling like an easy out or other bolt extractor because if it breaks off inside you'll have even more problems. Just use drill bits not grinding tools and you'll get it done. A grinding tool like dremel will not get it done
take your bits and wrap them with tape marking them 3/16in less than the thickness of the manifold at the bolt hole. This will leave a small amount of bolt that you'll be able to rotate out of the head.
Keep drilling until you finish drilling with the largest drill. You should then be able to pry the manifold off the remaining piece of bolt. Then rotate the bolt out of the head while on the bench
09-04-2016, 03:09 PM
Help-broken exhaust manifold bold- canīt remove manifold
. I can turn manifold up and down on that broken bolt, It is separated from head, but it is not possible to pull it out. Is there any trick for it? I need to remove manifold to uncover head bolds. There is no space to drill it out. I tried to brush it with dremel tool and diamond ball on it, but that bold is soooo hard... 
Or use some penetrating oil, and keep twisting and pulling on the manifold. Its just a little rust between the bolt and manifold. It'll come off.
