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Exhaust Manifold Issue

October 15, 2011, 09:54:53 am

We found a broken bolt from the exhaust manifold.  According to the diagram from Cummings, the manifold is in 3 separate pieces.  We need to remove the first piece (closest to the back door) and replace the gasket and 2 bolts.  The problem is that the joint between the piece we are trying to remove and the middle section is firmly in place.  Has anyone taken the manifold apart and how did you do it??  The other option is to remove all of it but then we are concerned that we may break the remaining bolts thus creating another nightmare!!  Help!!  Faith

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Re: Exhaust Manifold Issue

Reply #1 – October 15, 2011, 10:51:06 am

I don't fully understand your situation -we have a different engine.  I would say to not be afraid of breaking or cutting the heads off bolts to get the repair done.  Years ago, you might do some searching for a bolt.  Now, practically every home store and hardware store has a great selection.  I have encountered several repairs where it was easier to just cut the heads off bolts, get better access for removal, and replace the bolts with new.

oldMattB

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Reply #2 – October 15, 2011, 12:20:15 pm

Bob, My OPINION would be to completely remove the exhaust manifold, and face  what ever happens, new gaskets, studs, what ever.  Because when it is all done you are 100% done. If you only replace one piece to replace the gasket and broken bolts, in a few months you will be back into it, to complete the rest of the job.  As mentioned  this is my OPINION.  Ya gotta do what ever feels good. 
FWIW

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Reply #3 – October 15, 2011, 12:24:54 pm

I had to remove all of my 2 part manifold to get it off. A few months ago a friend was here with his MH and Cummins and as his manifold was cracked we had to remove his. I got out the acetylene torch and heated for a moment the engine block area around each bolt before trying to loosen it. They came out fine except 1 that broke and that was because it was the most awkward one to get some heat on due to its position. Once the manifold was off we drilled it out and used a stud extracter  (again heating the casting a bit first) without any trouble. Once they are all out make sure you clean the threads out with a tap and put some anti-sieze compound on the threads and bolts.
This is not hard to do and we found the most time was spent taking all the parts off than actually removing the bolts.
John

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Reply #4 – October 15, 2011, 01:53:15 pm

I took my 93, U225 to Cummins to have the "Pros" replace the exhaust manifold gasket because I was afraid I would brake some of the bolts and I didn't have a torch to heat the block. I should have known better, the Pros at the Cummins shop broke four of the bolts which required drilling out. They charged me three extra 3 hours, $315, due to the broken bolts that they should not have broken. They told me they did not use the torch because someone else in the shop was using it. They claimed on an engine 14 years old that you will always break bolts. I still don't believe it if you are careful but the cost for an exhaust manifold gasket on my little 5.9 was over $600 as I recall. FWIW

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Reply #5 – October 15, 2011, 02:20:41 pm

Thanks.  I think the best approach will be to try to remove all the bolts with heat and remove the manifold in one piece.  If the bolts break, then we will tap them out.  I will first remove the turbo to get some room down there.  I think that would be the best way to handle it and then everything will be new (gaskets and bolts).  Thanks for the insights.    Bob

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Reply #6 – October 15, 2011, 02:28:08 pm

In our shop, we have much better luck with rusted bolts in castings by only heating the end of the bot to cherry red, let it cool, then we have better luck removing it in one piece. We use a stud remover tool up against the casting as close as possible.

Sometimes you need a good vise grips camp tight, tap lighty with hammer in both directions to start working it loose and use pentrating oil too, hell what ever works. Sometimes you have to play with them, but breaking off is a no no.

Problem, hard to describe cherry red to some mechanics, some think you need to melt the bolt, wrong.

When reinstalling new bolts, use tap to clean up threads, air hose to blow out the trash and use anti-seize lube.
Cheers

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Reply #7 – October 15, 2011, 06:18:29 pm

I had to remove manifold, when making a mistake installing pyrometer and boost gauge.  I was not under time restraints and used PB Blaster.  I spayed each bolt once a day for about a 5 days till the next weekend. All bolts came out very easy without using impact.

Larry B.
1997 U270

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Reply #8 – October 15, 2011, 07:36:15 pm

It is actually not uncommon to have bolts break when removing manifold, but if you heat block up as I said it will minimize the chances. I do not suggest using an impact as if for some reason the thread is messed up with the power of the impact you will for sure rip out any chance you have of easing the old bolt out with a release agent, and then you have to put in a stepped bolt and that will weaken the side wall thickness in the casting. Heat it up and cool down a couple of times if needed, and use a good fitting socket and bar.
John

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Reply #9 – October 15, 2011, 08:55:39 pm

One small point about why we head the bolt to dull cherry red, then let cool back to room temp.  This seems to expand the bolt, then relaxes back to normal size, this usually makes it freer (more free).  Everyone has come to terms with tis type hassel, but for us, this works good. 

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Reply #10 – October 15, 2011, 10:15:55 pm

Dave, I was wondering the logic behind heating the bolt. Thanks for the explanation.

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Reply #11 – October 17, 2011, 02:55:39 pm

Everythings apart, cleaned up and ready to go back together. Does anyone know the torque specs. Found this on the internet, not sure what step 1 and step 2 means. Cold and hot? Is the torque spec with anti-seeze?

Exhaust Manifold

Torque Value: Step 1 27 n.m [20 ft-lb]
Step 2 47 n.m [35 ft-lb]

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Reply #12 – October 17, 2011, 03:18:21 pm

I have always understood, when two numbers are given, you tighten all the bolts at the step 1 torque, then go around again at the 2nd torque setting.  Sometimes there is a pattern to follow as well, for where to start and order of which bolt next.

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