Broken exhaust manifold bolts

Ok, I need sage advice from those of you who have solved this problem before. You will see in my photo link that the bolt heads snapped off of two exhaust manifold bolts when I was removing them. I have been soaking them with PB Blaster. But, I don't want to screw it up any more than it already is. http://s1199.photobucket.com/albums/aa472/Billywam/

 

Heat the broken bolts with an acetylene torch until hot then apply paraffin candle wax. Do this at least 3 times letting cool completely each time. After the last time let sit for several hours. They usually come out after that. Propane is not
hot enough. If that doesnt work heat em up wit the torch and quench the bolt with water at least 3 times then try the wax again. I've had very good luck doing this

 

i just delt with this same exact thing a few weeks ago. 3 outta five of mine broke when removing. the are a few options. try putting two nuts on the threads that are left. tighten them together (agianst eachother) and the second one you put on will help to hold the inner one on. slowly turn the inner nut to remove the bolt, just like you would if the bolt still had its head. second option, use a torch. heat the bolt and remove bolt with vice grips when not is hot. third and what i found was the best way, was to go to harbor freight and buy a tap and dye set. $12 or $13. grind down the bolt flat. use a center punch on the flattened bolt and drill out the center. start with a small bit. then go larger. drill out old bolt one bit size bigger than the hole (so no threads are left in the block). a nice clean hole is needed to tap. note__ dont drill to far!!!! use a toothpick to measure depth on a hole thats good and mark that distance on your bit. so you dont drill in too far. then tap out the hole and replace with a quality bolt(s) i use grade 8 bolts. use antiseeze on the threads when reinstalling. torque to specs. well that's what i did. some people might critisize this instruction, but it worked well for me. good luck!

 

p.s. stuff a rag in or tape off the exhaust port so the shavings don't go into block. also when tapping and going to a slightly bigger bolt, you may need to drill out the holes on the mainfold a bit bigger (for the bigger bolt going through).

 

IF there is enough left sticking out use a stud removal tool like this http://www.harborfreight.com/1-2-half-inch-drive-stud-extractor-94640.html If that doesn't work I go to left handed drill bits, If still no go, I use an easy out.

The most important thing is when you reassemble use the Copper colored anti seize. ( My opinion the silver isn't as good) I use it on every nut and bolt It makes the next time you doe something so much easier.

 

If you have a welder stick a nut over the remaining part of the bolt and weld the nut to the broken bolt. Do this with your welder on a high heat setting then let it cool. Some of the time it turns out but sometimes it just breaks the rest of the bolt off.

 

The paraffin works it's way into the threads creating a lubricant. It kind of wicks down inside. Some will burn off but as it cools it hardens back into a lubricant barrier instead of just tightening back up. Used it on winches, exhaust manifolds, intake manifold fittings, etc. Not a guaranteed fix but I've had lots of luck where penetrating oil wasn't enough. I had a pto winch I absolutely couldnt get the bolts off the driven gear without them snapping. 5 out of 8 broke off. I couldnt get them loose with penetrating oil, drilling and easy out, heat, nothing. Did the wax trick and came back the next morning and spun them out by hand. Ymmv.

 

If none of the other tricks work, before pulling the head, if you have an oxy/acetylene torch or access to one. With a cutting torch heat the bolt to bright red and trigger the oxygen lever, the bolt stub usually blows right out leaving a useable hole. It may be necessary to do this more than once to clean the broken stud out of the hole. If you think this will cut the cast iron of the head, try it first on a scrap exhaust manifold or head. Steel will melt long before cast iron. I've done this many times with good results. It will probably be necessary to clean up the threads with the proper tap, this is much faster than pulling the head, and I've never seen it fail. Good luck.