HELP! Broken Exhaust studs!

So I have a really bad exhaust manifold leak on my F150 5.0L. I got 6 of the 8 studs out cleanly. One was previously broken. One snapped. Both on front cylinder (#5) on drivers side. The previously broken one (main reason for the leak) is underflush to the head. i.e. nothing protruding and it's sunk in. The other one has about 3/8" exposed. How do I get these out?

And if anyone has an oxy-acetylene torch near Adrian, MI I can borrow, I'd greatly appreciate it!

I am not attempting the passenger side yet until I have the driver's side done. The pass. side also has at least one broken stud as well.

It's a little harder when they're flush, but my preferred method has been to MIG weld a nut on then simply crank it out. The heat from the welding helps loosen things up considerably. Of course, if you don't have a MIG this is rather useless advice.

I concur with 02Pilot

I've thought of that. However, it is broken off a good 1/16" into the head. I don't want to accidentally weld to the head...

Iron heads do complicate this somewhat; I've only dealt with aluminum. I suppose if you could find a piece of copper pipe or flexible sheet that could be used to create a sleeve you could then weld inside it and hopefully avoid welding to the head, but without seeing the exact configuration it's hard to know if this would be workable or not.

Damnit...I'm throwing in the towel on this one. I can't get to the manifold to downpipe bolts on the pass side. They need to be cut/burned off. And I just don't have the tools necessary to get the broken studs out. I've at least made access easy by pulling the inner fenders. Hopefully I don't get bent over too much on this one. Going to have it towed to a shop to have the studs removed and the other manifold removed, then towed back for reassembly by me.

Sometimes it helps to weld a washer to the stud first, then a nut to the washer.

Sorry to hear you throwing in the towel, but I totally understand the feeling of getting in over your head on a project without the right tools.

The suggestion to MIG weld a nut on and spin it out is great, it can be done easy on the stud thats protruding. On the stud that is flush, if there is access, I would gradually build up a nub on the stud with my TIG until its standing proud enough to grab it with a vice grip. Its a huge pain in the dick, but it works well. You can try MIG welding the stud, usually the weld doesnt stick too well to cast iron.

I have also successfully MIG welded out broken studs below the surface by very carefully applying anti-spatter tip dip with a toothpick to the walls of the stud hole then going to town.

How much are new manifolds? Some common ones can be cheap compared to fighting the studs.

CGLockRacer wrote: I've thought of that. However, it is broken off a good 1/16" into the head. I don't want to accidentally weld to the head...

meh. it's cast iron the weld won't stick anyway. nothing chasing the threads could not fix.

For one broken off below flush I would have reached for the drill before the welder. Start small and eventually either an easy out or helicoil will work.

+ Heat

Heat and Kroil, use a small carbide burr to make the face of the stud flat, centerpunch it carefully, then drill with successively larger LEFT HAND drills. When you get big enough the remaining shell will back out.

Well, I ordered some extractors with left hand drill bits, I'm borrowing an oxy-acetylene torch from a co-worker, and a 90 deg. drill from work. I've been soaking everything with penetrating oil every night. I should have all tools in hand by Thursday. I need to have everything back together by a week from Thursday. Problem is I'm instructing for 3 days on the other side of the state this weekend, have to work all week, and I'm out of vacation days. Wish me luck!

Picture of said studs. This is the driver's side, front exhaust port. The pass. side has a broken stud on the rear port, easier to get to at least.

The snapped off stud I will try to weld to again. The stud to the left and up of the spark plug is about a thread or two deep in the head.

Jesus want so much, this and heat will work as well!

A nice line of permatex ultra copper, and let the other studs hold it in place?

Heat the stud sticking out red hot with oxy/acc then quench using parafin wax, should come out easily after that. This is how you remove some plugs in cast iron engines.

this is one reason i hate working on later model stuff- once they figured out how to make valve covers stop leaking, you lost that constant supply of oil to keep bolts nice and lubed up..

for the one sticking out: heat up the metal around it with the torch then spray it down with some of the foamy PB Blaster... then smack the stud straight on the end with a hammer to jarr it loose and work the PB into the threads.. then put a small pipe wrench (not a vise grip) on it as close to the base as you can and apply steady pressure to it to twist it out... sometimes it will break free if you also hit the end of the stud with the hammer while putting pressure to it...

benzbaronDaryn wrote: Heat the stud sticking out red hot with oxy/acc then quench using parafin wax, should come out easily after that. This is how you remove some plugs in cast iron engines.

Is it possible to get generic exhaust bolts red hot w/ those "plumbers torches"?

Whups. I misunderstood. The broken studs were in the heads... No, you cannot get the head 'red hot' with a plumbers torch, but sometimes you can get it hot enough with one of those to loosen a stuck stud....

Was that motor previously stored at the bottom of the ocean? Holy smokes that thing is rusty!

And surprisingly the truck itself isn't that rusty. Not sure why the block/heads are. Here's the build thread.

http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/my-96-f-150-kinda-build-thread/55809/page1/

And for an update, I got the pass. side manifold off. I borrowed an oxy-acetylene torch from a co-worker. I need to get the one I have rebuilt. I got it for free, but it has been sitting for 25+ yrs.

So I have 2 studs that are broken in the heads (one pass. side, one driver's side), and one stud that is exposed (driver's side). I tried welding a nut to it again, but it didn't hold. Not sure if my settings are right on the MIG. I have one of these: http://www.amazon.com/gp/product/B000CODE0W/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
coming though as well as these: http://www.amazon.com/gp/product/B0002NYBH8/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

So hopefully I'll be able to get everything out and fixed. The shop I got a quote from gave me a price of "they don't want to do it".

Cut/grind until flush.
Drill out center, nice and straight.
Pull out remaining pieces.
Chase threads.

This process has been done over and over since the V8 was introduced.

I do a ton of these, on both GM and Ford. The Fords seem easier, because the studs are made out of better steel for welding than the ones on the LS motors.

The welding of the nuts is generally a "repeat as required" situation. The first one I usually count on to just remove the impurities from the stud so the second one will bond better. Don't just crank on the nut, either. Once its welded on, let it cool. Some people try to cool the weld with water, the theorey being it will be harder. I don't bother. I usually will beat it a bit to try to loosen up the thread a bit, then very carefully loosen-tighten-loosen- and I mean just a wee bit, until the stud starts to move. You probably won't be able to put more than, maybe 20 lb-ft of torque on it, even if its welded perfectly. A ratchet kinda sucks for this job, because you are forever reversing it. I have a small 3/8 breaker bar that works well, or will use a flat wrench if I have decent access.

I usually use 3/8 nuts on an 8mm stud, and I bring at least a dozen nuts with me. I think that bringing only one nut to a job like that causes the Gods to be angry with your arrogance.

Persistence will pay off.