Broken header bolt

[jcslocum]

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

[tommy583]

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.

[brewerbry]

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!

[texomawaves]

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.

[itsnotanova]

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.

[tommy583]

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.

[jcslocum]

Originally Posted by brewerbry

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.

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.

[Mark_T]

Originally Posted by jcslocum

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

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

[brewerbry]

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

[san rensho]

Originally Posted by jcslocum

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

Please heed his advice. Take the easy out now and throw it away. It will break off and you will not get it out. I learned that lesson with a moto. I broke off an easy out in the motor case. It cost me $750 to have a machine shop use a laser to vaporise the easy out.

[tommy583]

Did you ever get this sorted out. I hope it ended well.

[brewerbry]

I was able to clean out all of the old bolt with a tap and the threads are strong enough for an original (new) Porsche header bolt to not only hold but get torqued down and not leak.

What a pain in the butt! I spent 2 hours very slowly and carefully cleaning out the hole with the tap and got lucky that I did not mar the original threads.

No more exhaust work on this car for me!!