Broken stud in exhaust manifold, how to get out??
 

First off, let me start out by saying... ARGHHHH!!!!!!!!!!

The driver's side flange was a little loose so I figured while I was under the car doing fluid changes I might as well try to snug it up. I barely even put any pressure on it and the stud closest to the firewall just snapped, right flush with the manifold. So now the flange is really loose and the car sounds like a monster truck. What is the quickest and easiest solution to getting the rest of it out? I know this isn't going to be a cake walk. Its going to either take alot of heat or a really long drill bit to get up there to get whats left out...

I hate to say it, but I think the best approach is to pull the manifold and deal with it. I've never had much success attempting to repair a broken stud in a confined space like that and haven't seen anyone else do a good repair with them still attached either. If you need to drill the stud out, it's extremely difficult to get the right angle with the manifold still attached.

Ugh, thats what I was afraid of......

:o Sorry. :bolt: :beerchug:

Pull the manifold and soak the stud in penetrating oil. Let it sit a day and soak it again. Wait another day and then grab the piece still there with some vice grips and try to turn it. If it doesn't move, you may have to apply some heat from a propane torch but be careful with all of the flammables there. Try to ease it out by working it back and forth. Worst case scenario is you will have to pull the head.

After reading the initial post again, I realized you were talking about the stud in the manifold, not the head.:doh:

You should pull the manifold and work on it. It really isn't that hard. Just make sure you soak the manifold to head bolts before you start to remove them. For the stud, a trick that has always worked for me is to heat it up till it's red hot. You will have to use an oxy-acetylene torch to do this. Turn off the torch and then spray the stud with WD-40 or penetrating oil. Do that 2-3 times and they usually come right out.

Sorry for the initial mis-understanding.:o

If it is broken off flush you need to remove the manifold. Since it is a 3/8 stud you take a 5/16 bolt, bevel the end of the bolt and mig weld it to the remaining stud. Now you have something to turn with a wrench. Next step is a lot easier with a helper but is possible to do by yourself. Mount the manifold in a vice. Using an oxy acetalene torch heat the manifold up glowing orange around the bolt. While it is still glowing turn the bolt out. It is easier with two people so one can keep the torch on it. If you let it cool till it is no longer glowing it is much less likely to work. Someone will probably say this is not the best way for some reason. But after a machinist told me to do it this way I tried it and it worked like a charm every single time. Every other way I have tried was hit or miss at best. Yes it is more work and requires more tools, but if you have the equipment it always works. Or at least it has the 50 or so times I have done it.

always took it to the muffler shop and those guys have removed them for me. no problem for them. this is routine.

I took it to my regular guy this morning and he said he can't fix it. I might try one other place. I had a guy in Florida that could fix these things on the car all day long....What a pain in the arse....

Unfortunatly, When a stud is broken clean off to the surface, the only right repair is drill and tap.

I worked(managed) in the exhaust business for years, to get them out if still on the car, I (we) would take a nut the same size as the bottom stud size sticking out, 7/16 or 3/8 and get the manifold red (cherry) hot with the torch then push the nut on the stud as hard as we could and run the impact in reverse on full, It worked 95% of the time, other wise I would blow the hole out with a torch and just re tap, but you have to be good with a torch for that, Jim

My trick is left handed drill bits. Center punch the stud,start with a small drill,work up in steps to bigger sizes , and at some point the bit will grab the stud and it will back itself out.

The critical thing when drilling out a stud is to centerpunch the broken end exactly in the center. It will probably help if you can file the broken end flat first, so the punch (and then the drill bit) won't wander.

Even with a center punch it's not easy to get it drilled dead center. I've got the exact same situation on one right now---luckily it's a duplicate to what's on the car. I've got it mostly drilled out to where the threads start, soaked it in Kroil, and even with an easy out I can't get the remainder of the screw to break free.

The problem is the stud is very likely rusted in place. So not only are you trying to remove a bolt that is tight, it is also rusted in there.
There is an electrical process that will remove the broken stud. I had some broken exhaust studs in a b/b Mopar head many years that were removed with this process. I took the head to this place that specialised in removing broken bolts/studs. I am not 100% sure how the process works, but I believe the broken piece is subjected to a strong electric or magnetic field that causes the piece to 'vibrate' & loosen.

Another tip:

If the stud breaks off flush and if the drill bit wanders, I use progressively larger bits until I just start to hit the threads on the manifold. Then take a pick or drift punch and start bending in what is left of the stud closest to the manifold. There should only be the high part of the threads left so the stud isn't very strong at this point. After a while you will basically cave in one side of the stud and you can either unthread it or push/pull it out of the hole. It takes a while but has worked for me.

I hope that made sense.

I paid my local machine shop 15 dollars to fix the one on my z-28, Trust me cussing the thing dont work!!!!

I've had a pair of long branch manifolds I've been saving for my '66 but Im going to put them on this car instead. I've got all the new hardware ie bolts, oil adapter, flanges so tommorrow after I finish with my customer work Im gonna try to get the old ones off and get the LBs on. I'll run it to the exhaust guy the next morning to make new head pipes. Its gonna get some new Flows too so it oughta sound really nice. Going from a broken open header with glasspacks sound to LBs and Flows should be a dramatic change.

You're probably referring to EDM- Electrical Discharge Machining. It's a good alternative to know about, and a fair number of machine shops have the capability. There are a few limitations (shape of part, etc.) and it's not real cheap, since it's very time-consuming. But if you're ever stuck with a high-value part that has, say, a broken-off tap in it, it's just about the only choice.

I hate it when that happens! I've always taken mine to the machine shop. I think last time they charged $15 to remove it. Well worth the price if you ask me.

The best way I know is to heat the stud or nut etc. good and hot and spray with water. The exspansion and quick contraction breaks down rust etc. On small studs a vibrating pensil engraver worked counter clock wise works. The heating and cooling of brake lines has always worked for me.