removing broken exhaust stud- any tricks I don't know about?

BretLuter · **Posted:** Wed Sep 26, 2007 9:32 pm

So I'm swapping a "new" engine into an BMW E30, I decided to change out the crusty exhaust manifold gasket/heat shields- I got all the studs/nuts out OK except 1 broke while trying to remove it....

I had about 1/2" of the stud sticking out of the aluminum head- so I soaked it in PB Blaster overnight and then worked on it a bit more tonight. I tried turning the stud out using vise grips- but no luck. So I threaded a nut onto it, cleaned with brake cleaner + dried it off- then welded the nut to the stud, allowed it to cool- sprayed again with PB Blaster and tried to spin it off with an impact wrench. I managed to twist ~1/8" section of stud off along with the welded-on nut. Tried this again with the same result. Now I'm down to about 1/4"-3/8" of the stud sticking out of the head. I sprayed it down with PB Blaster and will allow it to sit overnight again.

Any great tricks that will help me get this thing out before I'm totally screwed and have to end up drilling + tapping the hole??????

This is an 8mm(?) diameter stud with a 13mm head nut on it, if it matters....

Bret.

ps- I tried tapping on the end of the stud with a hammer to help jar the threads loose a bit- but it obviously was not 100% successful......

Todd Breakey · **Posted:** Wed Sep 26, 2007 9:53 pm

Bret,

I have a stud remover sitting in my tool box. Not sure if it would help you but you are more than welcome to borrow it.

It is theis one here from Sears.

Ryan Storzbach · **Posted:** Wed Sep 26, 2007 9:53 pm

doh - I dont have any tips for ya, but I am going to cross post this on the GRM boad and hopefully one of the mechanic-junkies can share some tips. I'll be around after 5 tomorrow, and all day Fri-Sun so just let me know when you want to do some wrenching.

GRM Post
http://grassrootsmotorsports.com/board/ ... 68#p334168

PhilFausz · **Posted:** Wed Sep 26, 2007 10:28 pm

I've used a set of tools called by various names... easy-out, screw-out, out-extractor, etc. With this, you drill a hole in the bolt, as large as you're comfortable with (bigger the better) and put these tools on and it reverses the bolt.

Now, when I did this, it was on a 1/2" bold in the bed of a Jeep, not some rusted, been heated and cooled four billion times exhaust bolt.

Good luck. I hate it when something little goes so wrong that it turns into bigger than the original task at hand.

BretLuter · **Posted:** Wed Sep 26, 2007 10:47 pm

PhilFausz wrote:

I've used a set of tools called by various names... easy-out, screw-out, out-extractor, etc. With this, you drill a hole in the bolt, as large as you're comfortable with (bigger the better) and put these tools on and it reverses the bolt.

Now, when I did this, it was on a 1/2" bold in the bed of a Jeep, not some rusted, been heated and cooled four billion times exhaust bolt.

Good luck. I hate it when something little goes so wrong that it turns into bigger than the original task at hand.

Yeah, I've used those extractors too- but I'd say that ~75% of the times I've used them, they end up breaking off in the bolt you're trying to extract, so now you have a broken steel bolt with a hardened steel extractor firmly stuck in the center. If it comes down to drilling it out, I think I'll just carefully drill it out until I am able to turn the remains of the stud out bit by bit.

Todd, thanks for the offer- I'm not sure there's enough of the stud for that tool to grab onto, but I'll let you know if I need to use it.

Ryan- I'll be working late thursday, but Friday is still a possibility- and Sat and Sun afternoons are pretty much definite...... BTW- how do you know I'm a "gentleman"??? :shock:

Bret.

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

I successfully removed a broken bellhousing bolt from the Subaru block when the bolt sheared at the block surface during a clutch replacement. Took about 3 hours to get it out. Using a HF 200+ drill bit assortment, I drilled through the exact center of the remaining stud with a tiny bit then slowly incremented up in size until I suspected I was hitting the aluminum threads on the block. Jammed a screwdriver in there and backed out the remaining shell of the bolt which had loosened up due to heat, mechanical action, and occasional blasts of PB. It seemed like a miracle when I got it out and the threads were intact on the block.

Ryan Storzbach · **Posted:** Thu Sep 27, 2007 6:33 am

BretLuter wrote:

BTW- how do you know I'm a "gentleman"??? :shock:

Bret.

It was easier than trying to explain what a BMW-Farmer was :lol:

Ryan Holton · **Posted:** Thu Sep 27, 2007 7:18 am

I guess its a bad idea to apply some heat to it with the aluminum head?

Fire is always my first choice if available. I have never had much luck with ezouts, extractors or any other gimmicks.

Bernie Baake · **Posted:** Thu Sep 27, 2007 8:18 am

I don't know if heat is a bad idea, Marine mechanics use it on aluminum outboard engines ALL the time. If the outboard engine is more than three years old it's got siezed head bolts in it. I'll e-mail a friend on the coast and see if there's any special proceedure to heating the head.

WalterHouston · **Posted:** Thu Sep 27, 2007 8:18 am

I've done what Mike did and it worked. The key is to drill straight and work up from smaller bits to larger ones. On really tough bolts, I've uses carbide bits. I think the heat from drilling helps.

Donnie Barnes · **Posted:** Thu Sep 27, 2007 8:54 am

One thing that will help a bunch with your first hole is to keep your drill speed somewhat medium...fight the urge to let the drill really spin. Go slow. Also, use cutting fluid regularly. That will keep the heat down and your bit in tact. The fluid is much less important after the first hole as long as you go up in hole size slowly. You're also better off letting the drill spin faster in the later holes so that you don't have them "grab" and break the bit off.

--Donnie

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Totally agreed on Walter's and Donnie's comments. Getting that drill bit straight while working *underneath* the car was a challenge!

If you're lucky, while drilling out the bolt it will loosen up and try to screw in with the drill -- at that point you may be able to just reverse the drill and back it out. Nothing is ever that easy though, is it?

Once I learned (a few years back) that slow drill speed is the key to successful metal drilling, my bits last a lot longer and I'm far more successful chewing holes in metal.

BTW - while we're talking about drilling technique -- I should mention that one of my new favorite tools are step drill bits. Man do these make for easy large hole drilling in thicker metal. I'm going to buy another set of the HF ones when they go on sale for 5.99 again. Doesn't help for headbolt drilling though

Ryan Holton · **Posted:** Thu Sep 27, 2007 9:19 am

MikeWhitney wrote:

BTW - while we're talking about drilling technique -- I should mention that one of my new favorite tools are step drill bits. Man do these make for easy large hole drilling in thicker metal. I'm going to buy another set of the HF ones when they go on sale for 5.99 again. Doesn't help for headbolt drilling though

X 100

I just got that HF set and LOVE them to death.

MartynWheeler · **Joined:** Mon Jan 02, 2006 9:30 pm **Posts:** 303

Another trick when drilling is to use a left-handed drill bit. That way the drilling force is trying to extract the stud anyway, so if it starts to move it'll be in the right direction.

Ryan Storzbach · **Posted:** Thu Sep 27, 2007 6:15 pm

MartynWheeler wrote:

Another trick when drilling is to use a left-handed drill bit. That way the drilling force is trying to extract the stud anyway, so if it starts to move it'll be in the right direction.

Good idea

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removing broken exhaust stud- any tricks I don't know about?

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