Need advice to remove broken exhaust bolt

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i6pwr

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Of course the bolt that was broken was in the rear. I've been at this for quite a few hours, never has a bolt given me this much grief.

All the bolts didn't need too much to break free, maybe 40-50 foot pounds. This bolt has been broken for years, I'm going to replace the exhaust manifold so this needs to come out.

So far I have drilled and tried some Irwin EZ outs. I have tried to heat the aluminum, freeze the bolt, used quite a bit of penetrating oil, tried left hand bits,.....I think I managed about 1/4 turn but no more.

I did get the hole centered, if I drill any more I will be too close to the threads. I tried two sizes of the EX-Outs, they bite hard, but when it feels like it's going to give, the extractor gives.

Can I use a mig welder and fill the hole, then try some vice grips? I want to say that's my only bet unless I go all the way to a Heli-Coil and I'm trying to avoid that.

The hole is the lower left. Bolt size is M8X1.25.

Edited to add: I just ordered the Irwin Tools Hanson 53227 Hex Head Multi-Spline Screw Extractor Set, 25 Piece and will give that a try before building up a weld.





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Those spiral type EZ outs never work for me. What they do is add more and more outward pressure to the broken bolt as they are turned. That's counterproductive because all you do is run the risk of breaking the EZ out into the bolt hole.

In stark contrast to the EZ out, the PROTO square extractors work fantastic. They don't increase outward pressure as they are turned. The force is applied one single time when they are tapped in. It's the tapping in that provides the bite on the broken bolt; not the act of turning.

I recommend 1/32'' inch smaller in drill bit size than what's printed on the extractor; that way it doesn't have to go in so far to bite.
 
Originally Posted by DoubleWasp
I just Heli-Coil those every time. The one time you end up with an extractor stuck in a head, you're going to want to beat yourself silly.

+1
 
You are almost there. 5/16 =7.9mm. Run a 9/32 bit in and then use a pick to pull the rest of the bolt away from the threads. Use a fresh bolt or a tap to chase. The thread doesn't need to be perfect to accept a bolt
 
I could never understand when EZ outs or other extractors are useful. Its a tool I've used once in my lifetime (unsuccessfully). They are tools that take up room in my tool cabinet. None of any horribly rusted bolts I've encountered could have benefitted from extractors. It's always been torch heat or drill and retap.
 
I'm with others who stay away from bolt extractors. When I worked in a machine shop I can't tell you the number of times we'd get heads in with a broken off easy out with two drill bits broken off next to it. A few times we couldn't get them out even at the shop off the car and sent them out to have the extractor and drill bits removed with an EDM.

You're so close to tap size, hole is centered, why not just drill for tap size and run a tap in there? That's what I'd be doing.
 
Originally Posted by andyd
You are almost there. 5/16 =7.9mm. Run a 9/32 bit in and then use a pick to pull the rest of the bolt away from the threads. Use a fresh bolt or a tap to chase. The thread doesn't need to be perfect to accept a bolt


thumbsup2.gif
Thats what I would try next.
 
I hear you on the ez-out...this set I'm using is of high quality but I have had one crappy bit break before and I agree it was a nightmare at best.

I guess my best options are welding a nut, or drilling and trying a tap.

What sucks is I need to drive it Monday so proper planning is key.

My worry is if the drill and tap doesnt work, then welding a nut is out. I cannot see how it wouldn't work but that's a cramped area.

Pic of drill in that area.

20190419_190836.jpg
 
The only slight fear I have of welding a nut is the front half of the bolt breaking off when trying to turn. At that point I could drill the remaining bolt...what a show...
crazy.gif


Is there enough meat left to try welding? Of course a whole bolt that isn't hollow would be ideal.
 
Hold a nut with a pair of vice grips turn up the heat on the welder and just fill the hole until you fill the center of the nut
 
Originally Posted by mattd
Hold a nut with a pair of vice grips turn up the heat on the welder and just fill the hole until you fill the center of the nut



This. I would have tried welding first before drilling, or just drilled a small hole first then weld. But the heat from filling the hole should make it come free.
 
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Using a mig welder is the ONLY reliable way to get one of these broken bolts out. Your previous removal attempts are going to make this difficult. If anyone else reading this runs into this situation, do not attempt to drill the broken bolt and use an "easy" out, go straight to the mig welder. Use the highest heat setting. For anyone wondering about this, NO, you won't weld the broken bolt to the head.
 
We are going to try the mig option. Need to get adapter as my generator has a 4-prong 50A and the welder has a 50A 3-prong.

I agree about using the welder first. Only reason I tried drilling is the other 8 came out easy, the stud I had was removable with vice grips....didnt think this would be that stubborn.

I do understand that the spiral tap adds wall pressure so I accept that's why it won't turn.

Life lesson here for sure.
 
Originally Posted by i6pwr

I do understand that the spiral tap adds wall pressure so I accept that's why it won't turn.

Life lesson here for sure.


Plus if the spiral tap breaks off in the hole, you are pretty screwed. They break without any warning, you can't feel it. Then you have a really hardened tap stuck in the hole. Then you will need expensive true cobalt bits to drill out, as regular HSS, titanium coated, cobalt coated bits will not touch.


Mig it. I learned that not long ago.
 
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