8.1 Workhorse exhaust bolt broken

[Ready2BRetired]

Have an 8.1 in an 05 Tiffin. Rear most pass side exhaust bolt broken below the mating surface. Any ideas w/o removing the head? Possibly have room to drill and tap not sure. Anyone ever use the KRAL brackets instead of removing the bolt? Open to all suggestions. Really don't want to remove the manifold itself as I believe I would end up with several more broken.

[wrgrs50s]

I just watched a Kral video and was impressed with that option. Thanks for sharing your fix, I learned something new today.

[cm2785]

I just had the Banks headers installled and the exhaust guy said the bolts on the end always break. It’s from the manifolds expanding and retracting. The Banks headers have a 5/8’s flange so it won’t happen again.

[falconbrother]

I try to weld a nut over the broken bolt/stud and twist it out. But, if you're broken too deep that option is out. It has worked 100% of the time for me. I tried it on a bigger bolt a couple of months ago with a stick welder. It didn't work. The MIG welder does a much better job.

[Ready2BRetired]

Put the Kral clamp on and seems to have cleared up the leak on start up and continues to stay quiet under load. Hope it continues to work well at least till other studs let go then we'll have to tear into it. Clamp was $42 shipped.

[T18skyguy]

You can buy left fluted drill bits that do their cutting on reverse. While it's drilling the bolt will loose it's strength and spin out with the drill bit. One thing to think about is if it breaks again and leaks long enough, the hot exhaust can start to burn a channel at the head. At that point, you can't seal it with anything. If you google "broken exhaust manifold bolt" there are many good examples of ways to do it. I like this way myself.

Tig method

[Jim]

What I did when I discovered a broken header stud was make a trip down to Mazatlan where they have many great diesel mechanics. Took a header gasket with me. The mechanics I hired to change all the header studs (Cummins 5.9 was known for studs breaking because of the gasket design) plus other work, called a 'specialist' for the broken stud. That guy had all the equipment needed and had it out within 30 minutes. Cost was $30 USD. Than $60 USD for the other work.

Kinda cool and I had a nice tropical vacation to go along with the work.

There are mechanics that know RV big gas engines down there too.

[liborko]

I removed several broken studs by drilling(carefully) 1/8" hole and spraying WD 40 thru the hole. Let sit overnight and use easy-out to remove broken stud.

[Ready2BRetired]

I would like to go the header route but in doing so I'm concerned in removing existing manifolds I will end up with additional studs breaking which would then require head removal. Kinda rock and a hard spot thing...

[T18skyguy]

Make sure you use a drill stop. On a Ford, there is only a 1/4 inch of metal at the bottom before you get into the water jacket. Might be the same on the Chevy. IMHO, going to headers after the fix is the best solution. If the exhaust manifold itself is warped greater than .01 inch your going to have a return of the same issue. Go to Banks or Thorley headers.

[ArchHoagland]

Let us know how it goes.

Workhorse dealer tried drilling out one of my broken bolts and wound up replacing the head after drilling through a water jacket.

I'm going with aftermarket headers the next time I have exhaust manifold problems. Been through manifold problems twice now.

[Ready2BRetired]

Thanks for the replies. I've decided to try the Kral clamp specifically designed for this issue. For $42 it will be worth it if it works till another stud breaks. Then it will be
time to remove the head I reckon.

[RLS7201]

As already noted. The easy way is to remove the manifold. Then hit the stud on the end with a hammer. That will shake it loose. Clamp on with vice grip and take it out. Those advocating changing the manifold gasket are at least 30 years out of date. Exhaust manifold to head gaskets are a thing of the past on OEMs. Before reinstalling the manifold, have it surfaced at the local machine shop. Then rub the exhaust ports down with a wet stone and mineral spirits, to clean them.

Richard

[Harvard]

I have had good luck with Grabits on Ford V10 broken manifold studs.

Grabits

[wrgrs50s]

It's not likely you can drill it out with any success. The way I've done it before is to remove the manifold and sometime there is enough of the broken manifold bolt sticking out of the head to get vice grips on and turn it out, but if not enough sticking out, place an oversized nut over it and then spot weld through the nut to the bolt. Let it cool for a few moments and then turn it out. If the broken bolt is recessed into the surface of the head you will probably have to remove it and take it to a reputable machine shop.