Broke a GM head bolt this afternoon. It's one of the shorter M11 bolts right at the front of the block so it's easy to get to (thankfully).

So I cursed my luck and went out, bought a couple titanium drill bits and an easy-out. Drilled it in there pretty good, stuck the easy out in there nice and tight. Got a quarter of a turn maybe, then snap. Stupid easy-out broke.

I've been drilling for the past hour almost and don't seem to be getting anywhere. The titanium drill bit isn't doing much on the easy-out piece that is now stuck in the bolt which is stuck in the block. Mouthful...

Anyways, this is pretty urgent because I need my car back tomorrow. The bolt is stuck about 3/4 of an inch in the block.

 

There is only two ways you will get a harden easy out out and that is you need a carbide drill bit or you have to EDM it out. Some times if you are real lucky you can break it up but 9 times out of 10 it will not work.



Just thought of some thing is any of the bolt showing or can you get to it to weld another bolt to it.This might be your only shot.

 

broke an ease-out once.....had to brake it out and then hela-coil the thread ......thankfully it wasn't in anything major.....

 

have you tried a left handed drill bit

 

An easy out is harden a standed drill bit will not touch it it has to be carbide.

 

Yeah my vote is for the welding method, hopefully the end of the easy out isn't too far down in the hole. If is below the rim of the hole, you might still be able to shoot down the hole with the MIG turned up hot and build the metal up until you can weld on a nut. The fact that the block is aluminum will help you, since the steel MIG wire will only sitck to the easy out, not the aluminum.

 

It is 3/4 of an inch below the block surface.

So it looks like my best bet for tomorrow morning is hunt down a carbide drill bit somewhere and a left handed drill bit (wish I tried that first).

 

They both have to be carbide you can get them at MSC By the way they are not cheap and don,t drop them they break easy.

 

Jd13;

You need an understanding as to what most probably happened to your bolt to see the most advantegous way to remove it.

The bolt has most probably been seized and galled by unprotected contact with the aluminium. Galling is, in simple terms, a cold welding event. Once two parts have galled, disassembly is difficult or impossible.

That is why your easy-out broke. The torque necessary to overcome the galling of the threads is greater than the tensile strength of the removal tool.

If you continue to operate in this fashion, even if you are successful with drilling with the carbide bit, you could strip the threads of the aluminium while removing the steel bolt.

If you want to save the engine block - yes it's probably come to that!
If you want to save that engine block, call a machine shop to have the bolt extracted & a heli-coil insert installed.

Yes it's expensive. Yes it's time consuming.
But I'm betting right now you could soak that bolt in the BEST penetrating oil bar none, Kroil - all night - and IF you could drill a straight hole in a hardened easy-out without a drill press, and without "walking" the bit, the carbide remover could break just as quickly.

A machinist would use a drilling machine to remove all of the offending bolt and then overbore the hole to the correct size Heli-coil insert, WITHOUT harming the head. The heli-coil would actually present threads that are stronger than your origional fastening system.

I would not try to hand - machine on the car. A few brave souls would, and they're lucky. Others on the board would encourage you to keep trying, but it's not their luck they're testing, nor your engine block they are risking.

Take a big breath, rent or borrow a ride to work. Consider this to be a learning experience. Never exceed the running torque when removing a steel to aluminium fastening system. Time, Kroil, vibration, a little heat and patience are your only allies when a bolt becomes stuck during removal.

Don't rush your decision, and Good luck!

 

I beleave the bolt is broken in his block not the head.And yes you are wright about cold welding.

 

Not sure if you saw,but its a bolt in the block.He said he broke a head bolt.
Its not the easiest thing to do to pull a motor.I'm sure worse case sceneiro he would have to pull the block.
Like most have said,i'd try the carbide bit and go from there.

 

Hmmmm, yes, I get the idea. I modified my first post to reflect where the bolt is really broken off.

Well, still you'd have to ask yourself, would you risk walking a bit into the block?!

Contact a machinist, they will probably suggest a method a drilling fixture could be attached onto the head surface w/o marring it. You've still got to drill a quality hole!