vanny_david

My header bolt was broken and I am planning to buy a power drill + drill bit + extractor kit to get that bit** bolt out..

Since the header bolt are grade 10 bolt, so I need some advice on what kind of 1/8" drill bit I need to drill it ?

Thanks,

Dual-500

There is no magic drill bit. Numbers of bits are the answer and a careful hand.

Use cooling liquid like WD-40 when drilling and be careful. Buy several bits to do the job. Cobalt or any decent quality bit is good. Start small and work up in size. The bits will have a tendency to walk around. When they walk around it will chew up the aluminum threads. Chances are you won't simply be able to center drill the broken stud and remove it.

Most likely you will have to drill enough of it out to drill the hole out to a special tap size and install a Heli-coil in the hole to repair it. Not a big deal.

hondamark35

you could try to find a reverse-fluted drill bit. if the drill bit bites down or grabs, it could loosen the bolt. i've used them before, but i know they aren't easy to find.

cibao2ner

heat up the header bolt 1st...the easiest way is to weld a nut to it the heat will loosent it up and then you can unbolt it

99blackcivicSi

i've always had good luck with an auto centering punch 1 small pilot hole and 1 larger hole then an extractor bit and bam its out, when you install your new ones don't forget to anti seize them

sdubfid

I see you are in vancouver.

I usually tig weld onto the bolt to build it up then put a nut on it to remove it.

I've done this on hundred and hundreds of turbos and it's the best method I've found.

vanny_david

Today I purchased both #1 Extractor, I could always return one of them
but the thing is.. which one would work best ??

Dual-500

I've only used the type in the first picture. The bottom may work better in a hard stud. Just guessing as I don't have any experience with that style extractor.

Good luck with it.

vanny_david

The thing is... the other half is deep inside in **** hole....

welding won't work

Dual-500

That's an assumption I made without asking and really should have asked you.

Assume also the header is off the engine? Is head on engine? Engine in car?

You may end up having to Heli-Coil it - no biggie.

The other guys gave some good advice. I've even used vice grips and grabbed the stud if it was sticking out and had something to grab on to - then simply unscrewed it, removed and replaced.

Be as careful as you can to keep the bit's from walking around when drilling. A small piece of tubing in the hole helps when you have a deep enough hole to hold it in place. Anything to keep the drill bits from tearing up the soft aluminum threads.