Broken Exhaust bolt 390
 

Hello People,
First post here, Trying to fix exhaust leaks on my 73 F250. After finding several loose bolts on the driver side exhaust manifold I decided to take off the manifold and replace the gasket. Most of the bolts were easy to get out, but the top bolt on #7 broke off with about 5/8" of the old bolt sticking out of the head. I've been using PB blaster, and heating the head a little with a propane torch, but I cant as of yet get whats left of the bolt to budge. Any idea's?? I'm leery to do anything else in fear of breaking it off altogether and having to pull the head. Also, It had the metal gasket/ heat shield on it, should I replace it with the same type ? or would a header type gasket be better? thanks...Tom

Keep soaking it. Heat won't help since that bolt has been heated and cooled a thousand or two times.
Soak it some more. Then try to screw it back in. Soak it some more. Try screwing it out. When you feel it start to tighten up, stop. Soak it again. Repeat as many times as it takes to easily work it out of there.
Could take a day or a month.
The stainless heat shields are all this motor was designed to use. Spray them with Copper Coat and torque them up. I double coated mine and sprayed the head and manifold mating surfaces too. I ran the motor then torqued the bolts again while hot. So far so good.
Thanks to the Masked Rider.

You can tap on the end with a hammer to help free it. Also the heat may help draw the fluid in farther. What are you using to turn with? Autozone loans a stud wrench that is pretty effective.

Thanks for the replies, there was enough thread for me to double nut the end of the stud. I think the nuts are starting to strip so I pulled away before I broke anything else. Autozone is real close so I may take a look at their stud wrench on the way home from work Wedensday. Seems like I had a good bite on the stud with the double nuts, It seems to be determined to stay put for now. Soak some more and try again later I guess....Tom

The propane torch is like taking a lighter to it. You need a real torch to heat the casting up around the bolt. If it won't come loose you might need to drill through it and use a square type extractor but once again heat it before pounding the extractor in. Or it can be drilled out and threads chased if you know what your doing. I've done plenty and its always same story the ones on the bottom always come out and top rarely does. Good luck

I agree and have BTDT as this post states. Also, the old stock bolt is softer than the casting, I've melted the bolt out with a torch and used a tap to clean the threads as a last resort. Use new copper hi temp lubed grade 8 bolts.

5/8-inch stickout? Weld a nut on it and back it out the "normal" way.

Might as well do the other side and installl headers. :)

Yep. Time to weld a nut to it as stated above. If that doesn't work you'll need the red wrench.

Upon install of the new bolts or studs coat the threads with anti seize and that should prevent that from happening again. May want to invest in some stage 8 locking fasteners as well to keep them tight. FE heads are notorious for loosening manifold bolts.

Ck out the liquid "freeze out kit" at the local auto parts store. If the weld a nut trick does not work, you can very carefully drill it and use an easy out.

Cauation use QUALITY drill bits and easy outs. It is NO fun when you break them off in the hole. As me how I know....

Before drilling you must punch a small centering hole in middle of the broken bolt, other wise your drill bit will be off center. And that can lead to more problems, so make sure you do that.

Drill it, then easy out it, it that fails, you can drill and retap the threads. And it that fails you can drill it and insert a heli-coil set up.

Again, Thanks for the replies,
Did I mention the engine is still in the truck? sorry if I did'nt, I don't have a welder to to weld a nut on the stud, but I'm concerned even if I did, the nut would break of as before and I would have even less of a stud to try and get a grip on.Drilling is not an option as this is the # 7 hole right next to the steering box. Is this an easy fix for a well equipped "mobile' mechanic? With my limitations it seems a daily spray of pb blaster and the waiting game is my best shot at this time. I just had a dual exhaust setup installed at the local muffler shop, there was not much left of the original muffler. Not real pleased that I had to do other repairs after having this done. He did not want to mess with the exhaust manifold for this reason, I probably went to the wrong place, live and learn. Every one here says headers are the way to go, I thought about it , but in the past it seemed like gaskets were always blowing out, I just wanted to fix it and be done....Tom

A right angle drill should work while in the truck. That's what inward thinking anyway but failed to mention it first time.

Welding the nut on works really well. After welding the stud is very hot. Spray quickly with penetrant to cool and shrink and it usually backs out easy. Do you have a buddy with a MIG that can come over and hit it for you? In truck shouldn't be a problem.

As long as you have threads to work with, plenty of PB and some patience you will get it.
Can you turn it at all?

It still will not budge