Broken header bolt
 

Long story short, I have a broken header bolt. I have drilled it out and have an easy out in it and the bolt still won't budge. I read about using heat. I have a propane torch I have tried, heating the surrounding metal for about a minute....is that too short? How hot should it get? Any other suggestions / ideas?

Help!

In this situation I have drilled through the bolt then used progessively bigger bits to remove bolt material until the drill reaches the thread inner diameter. Expect to use five of six bits each just slightly larger than the next. Use an adjacent hole and a drill depth stop so you don't drill the head. Pay close attention to lining the drill up with the axis of the bolt. When the inner thread diamemeter of the bolt is reached the bolt usually loses structural integrity and can be removed with an easy out or occasionally a screw driver. Whatever you do don't break the easy out in the bolt. Good luck. If you are really lucky the bolt breaks loose while you are drilling it.

Try heating the bolt, not the surrounding.
It will expand the only way it can and loosen.

If you aren't really familiar with using an open flame under an engine - I suggest just drilling. The flame method may work but the collateral damage potential if you are not experienced could be sad.
Be very careful drilling because the bolt is hard and the surrounding metal very soft.If the drill bit goes off alignment and starts removing aluminum ......
Have you saturated the offending bolt shank with Kroil or PB Blaster?
In the past I have suggested replacing these bolts with s/s studs+Blue Loctite. The correct grade of Loctite on the bolts helps prevent the corrosion but does nothing to stop cross-threading. There are appropriate size stud kits on EBAY.

Be very careful with the easy out. They are brittle like candy canes and very, very hard. If you break it off in there it will NOT drill out. Heat is your friend here, I will disagree with Ben above (he makes a great shifter!!) about the heating. Heat the surrounding head area to grow the hole larger not the bolt. Propane might not be hot enough but it is worth the try. Propane isn't hot enough to harm aluminum so heat for 2 min and try to loosen. Then addd 2 more min. Then let it cool down and start again. Do not heat with the easy out in there.

What size have you drilled it out to???

Do you have all of the other studs out already???

Stomski makes this kit for exactly this job:

https://www.stomskiracing.com/products/boxster-996-997-exhaust-bolt-repair-kit

https://cdn.shopify.com/s/files/1/06...g?v=1419030364

This is the main reason I haven't put on aftermarket headers. If you saw my thread on my brake caliper bolts you would understand. I wish you luck.

I have drill out the stud as large as I am comfortable with doing using a hand drill - there is hardly any bolt left. It is just a gaping hole (do not remember the exact drill size) but there is just enough material left for a big easy out to bite on to. I have learned that you can drill out an easy out if it breaks - use several cobalt drill bits and a lot of patience! I gave up yesterday but will work some more tonight on this.

I think I will heat the whole thing with the propane torch and see if it loosens at all. Let's all be realistic with the torch - it is not a precise instrument and you end up heating both the both and the surrounding metal, there is no way to only heat one or the other. Regardless, I will apply heat for a couple of minutes and hopefully it breaks loose this time.

I guess if the heat and easy out do not work, I can just cut new threads in the drilled out bolt - the thread size is M8 course thread (.125) correct?

What a pain in the neck this has been!

I've had this happen and decided to let the professionals handle it... took it to a machine shop and they fixed it for $20 in only a few minutes.

Why did you take the bolts out? Were you putting new headers on? Is this the only bolt that gave you problems? I hope you are able to get it out, what a nightmare.

I spray penetrating lube on every exhaust bolt before I ever even attempt to loosen them. I also always use propane on the header bolts. I've had a few break and I had one were the drill bit broke trying to drill it out. I had to mig weld a puddle to the bolt and build the puddle up to where I could weld a bolt to it.

Gorgeous kit but sheesh... $342 US... that would be an absolute last resort!

I got into this mess because I was going to add headers...I would love to know how someone was able to get a machine shop to handle this with the engine still installed in the car! I am not aware of many machine shops with a car lift but maybe that is more common than I think it is. Plus then I would have to either drive there with the exhaust manifold off or re-install the manifold for the drive over and then remove at the machine shop, fix it, then reinstall.

I will keep trying heat...and yes this was the only bolt that gave me problems

No heat isn't precise but the ability to transfer heat is. Heating the surrounding metal of the head allow the head to expand and grow the hole. The transfer the the bolt is very slow due to the corrosion and the poor contact between the alum thread and the steel thread. The transfer takes time and give you a short time where the hole is bigger than normal allowing for loosening to happen. Even in a steel head this works well.

Be patient and good luck.

Use a heat shield to protect vulnerable parts nearby ,particularly above.
If you have used penetrating oil - be careful ! A spray bottle of water may be useful!

If you get to the point that you need to put in a helicoil I've a thread on here somewhere on how to do it without the uber expensive tool. You will need a drill press to use that method.

Which bolt is it? Is it the one closest to the chain case? I bet it is.

penetrating lube
 

The best ones I have found are Kroil and PB Blaster

I went through this on my Boxster a few years ago. I bought all the special tools, searched the Internet far and wide and after months of wasted time and money I took it to a machine shop. It was not easy finding someone to do it, car ships wouldn't touch it.

Is there any sticking out ?, if so you could soak it in Kroll or Pb for a couple days, put a nut over it and tack weld the nut inside to the stud and try and back it out that way

I mig welded mine, snapped 3 of them.
First came out with just 2 nuts welded, the second needed 4 and the last one needed 9.

I hope you get it out.

http://i775.photobucket.com/albums/y...124_151753.jpg