I was trying to take the exhaust manifolds off a small block Chevy engine yesterday.
Got all the bolts out but one. Of course, theres ALWAYS one isn't there?

I was using an impact wrench and sure enough, one bolt twisted off flush with the head.

Whats the best way to remove it? I know there are bits called EZ outs but I've never really used one.

Do you use an EZ out with the drill running in reverse or forward?

What size hole should I drill in the bolt prior to using the EZ out?

Thanks for your help and any advice to make this task as easy as possible!

There are a bunch of ways to skin this cat. I think the EZ out MAY work. The way an EZ out works is you drill a hole (the drill size will be on the bit itself), beat the thing in the hole and use a wrench to twist it out. The bit has spiral flutes on it that are in the opposite direction of removal so as you turn the bit out, it will try to screw itself in. Problem is, the exhaust bolts are so hard it's VERY hard to drill a hole in the middle of it without the drill going off center and getting into the cylinder head.....bad news. If you have access to a welder try welding a big washer to the broken bolt then weld a big nut to the washer and try getting it out that way. We do this alot at work with bolts breaking off in turbocharger exhaust housings. It works most of the time but doing it in-car might be a bit of a challange. Try this before you do anything, heat the bolt area up with a torch and take a birthday candle or some sort of paraffin wax and rub the wax around the bolt. It doesn't have to be red hot but just hot enough to melt the wax. Let it cool completely, then go about with whatever means you come up with to remove it. The melted wax will get wicked into the thread area and act as a lubricant. I've done this and it has worked. The wax will stay when WD40 or stuff like that dries up and evaporates. Worse case is you'll have to remove the head and have somebody get that thing out. Good luck!!!!

I am in a similar situation with a broken starter bolt. Are those bolts soft enough to drill a hole in with a EZ Out?

Hello, bigbranz. The starter bolts should be soft enough to use an EZ out. Get a center punch and hit the middle of the bolt to help the drill bit stay it's intended course. Use a small bit for the first hole, like 1/8", it's easier to control, then use the size the EZ out calls for. Oh, use safety glasses, too. Metal in the eye sucks big time!!!!

Great...thanks for the info.

WarPony,

Thanks for the info. Gonna try and tackle that beast tomorrow.

By the way, the engine is out of the car, so the welding method sounds like a good thing to try.

After the melting wax has cooled, I would try this before welding on a washer and nut. Use a small chisel or center punch to attempt to turn the bolt out of the hole. Place the chisel or center punch near the edge of the bolt and tap it counter clockwise. It will dig in and cut some grooves, but that will not hurt anything. Easy at first but increase the force as time goes by. I have had good results doing this. Just stay close to the edge of the bolt so as to get maximum turning force but DO NOT HIT THE HEAD.

Good luck.

If you have to drill it and use a EZ out be real careful that you don't break the EZ out off in the hole, because its almost imposible to drill out a broken off EZ out,because there made of case hardened steel.

I did purchase an EZ Out and got the broken piece of the starter bolt out this afternoon. Thanks for the advice.

All the methods will work most of the time, they have for me over the years. Oh,, the trick with welding a washer and a nut idea,, that'a a new one on me !!!

But don't for get one thing when replacing the broken bolt. Always tap the hole out with the correct thread tap. and, always use a anti-seeze compond on the new bolt.

or,,,,, you can use a stainless steel raplacement bolt in the future, this may be the answer for all bolts. But god help you of you brak off one of thoes...+

And stll onre more trick.... the next time you have a bolt that won't come out, try to tighten the bolt first ....but not too much, then try to loosen the bolt the correct way.



James84ekly,