How To Broken Exhaust Stud Removal

[toybreaker]

put this here for input, mods feel free to move or delete /ubbthreads/images/graemlins/wink.gif



Notice the little buggers always break just below the surface, and usually at an angle.



Center puching the exact center will give us a place to start.



Did I say the exact center? .... /ubbthreads/images/graemlins/rofl.gif ...

It may take a few shots to make a starting point, but now is the time to pay attention. You will be basing every step after this on the center point, so time spent here will pay great dividends later.



Drill a small, short hole with a 1/16th's inch bit.

It doesn't need to be deep, just on center.

 

[toybreaker]

Fill the hole with lubricant, and drill all the way thru the stud with an 1/8th inch drill bit. It will relieve some of the tension, and also allow you to get penetrant to start working from the inside.



A good drill bit, some lubricant, and the shavings should look like this. If they come out blue, you're getting things too hot, and run the risk of killing the cutting edge of the drill bit. Taken to extremes, this will result in breaking the bit when it won't cut and you start pressing too hard trying to get it to cut.



Once I get to 1/8th inch, I start using left hand drills.

I usually go up in 1/16th inch increments, and most of the time, the broken stud will back itself out.



Sometimes, an extractor is needed.

helpfull hints

Use penetrant/lubricant at every machining step.

Your tools will keep their edge longer and operate cooler, prolonging their life and effectiveness.

If the drill bit won't cut, get another that will. You should get curly cue chips when you're drilling at the right speed and feed. (like in the pics) I buy quality 1/16th and 1/8th drill bits in bulk, ten at a time and just pitch them when they don't blaze thru the workpiece. Lifes too short to be drilling triangular holes in slow motion.

Done right, most broken hardware will come out during the left hand drill phase, and you'll rarely need a thread extractor.


If an bolt extractor/easy out is required, use a good one.

Removing a broken easy out is very difficult.


I've always felt that easy outs have a fairly short service life, especially the cheap ones. If you really tweek on them, they wind up, and that's bad bad bad. They are made from a really brittle material, and if you see it winding up STOP...you're seconds from disaster...

Drill the hole bigger, and use the next size.

You want the extractor to be biting about half way up it's length.

Any lower, and you're on the thinner, weaker section, and you're flexing the whole fluted section.

Any higher, and you're going to expand the top of the stud into the workpiece, making removal more difficult.

If you see any damage to the flutes, give it the navy flotation test. (toss it in the nearest body of water, if it floats, reuse it. /ubbthreads/images/graemlins/wink.gif )

Good luck, take your time, and good things will happen.

 

[G]

Nice write up. A few notes, if you break a drill bit off in the hole you are fuxored /ubbthreads/images/graemlins/smile.gif !!!

Once you are ready to back the broken bolt out heating the head area only, helps.

Also looks like you did this out of the vehicle which of course is much easier. Doing it in the engine bay can be a pita without a right angle drill.

 

[icurunnin]

Nice write up and good info as always /ubbthreads/images/graemlins/applause.gif
I removed my turbo mani to find that someone has already helicoiled two holes and a few more are fubared. I am going to try and re-tap all of them and hope for the best to keep the stock stud size.

 

[fivestardsm]

Very Nice!! I am so glad you wrote this up. It will be a great link page to those who don't know how. I have seen so many messed up because of mis-guided atempts.

There is another way to do this with a steady hand and a welder. It is very simple and quick. Has anybody else tried it? Since I learned the trick many years ago, I have only had to drill out several busted bolts because of dificult circumstances that would not allow me to use the welder method.

 

[Dialcaliper]

Nice writeup - this applies to pretty much any tough to remove broken bolt or stud.

One comment I might make is about the drill speed - as mentioned above, the chips should not come out blue. The correct drilling speeds for steel are actually *very* slow, with plenty of pressure - don't just run the drill at full speed and graze the surface, or you'll just heat the bit up and dull it. A proper bit should run slow and bite into the steel, leaving large chips. Also, a set of machining quality high-speed steel (HSS - typically the bits with the shiny finish instead of black oxide) drill bits works wonders over the cheap carbon steel bits you get at the hardware store.

 

[Lonewolf64]

Mods, can this be moved to the How-To section? This is great information, thanks!

 

[FlyingEagle]

This is the exact technique we were taught at College (GM ASEP Program), and I have to give you a pat on the shoulder for starting the hole dead center in that bolt.

If anyone comes to the point where they have gotten off center, which would include my first attempt at stud removal in engine bay (tight C53a confines with a straight electric drill), you will be needing some HELI-COIL's or TIMESERT's. Drilling the hole oversize and then tapping it as specified on the helicoil kit to accept a new threaded section. HELICOIL's are good and will work just fine, but TIMESERTS are used by many factory engine makers like Cadillac and GM (Ecotec) on their aluminum engine platforms.

I was commenting to my teacher about hearing of the TIMESERTS, but couldn't put my finger on where this information had come to me (it was from members here), and low and behold, his tool set for a Cadillac aluminum engine was sitting in from of us. Right there I stopped talking and laughed, it was plastered with TIMESERT labels.

This write-up and the other one with the welding technique [https://www.galantvr4.org/ubbthreads/showflat.php?Board=UBB11&Number=767271&page=0&fpart=1] for rusted/hidden snapped bolts, is something everyone is going to have to know at some point or another. Great job! /ubbthreads/images/graemlins/worthy.gif