exhaust manifold stud broken

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Jul 11, 2015 | 12:18 AM
  #1  
94 3.9L Magnum
I went to tighten the stud and it snapped. It was already broken since more than half of the surface of the break had old soot on it. I expect someone else started to try and stopped before breaking it all the way.

What size are the studs and bolts?
What is the best way to go at removing them and the bolts without breaking them? I expect I should replace them all both sides.

Does anyone know of a good source for an OE Y pipe that isn't all corrugated looking in the elbows?
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Jul 11, 2015 | 09:56 AM
  #2  
According to Dorman, and matching my LA 1988, they're 3/8-16 thread.

http://www.rockauto.com/catalog/rafr...parttype=13936

If they're in bad enough shape, cutting them flush with the outside of the exhaust manifold, removing the manifold, then soaking in Kroil or PBlaster repeatedly for a few weeks (!!) may be the best choice.

As to "OE y pipe that isn't all corrugated looking" - that's a contradiction *grins* However, a competent muffler shop with a mandrel bender can make one for you. If you buy an OE pipe, it'll be crimped at those points (that "corrugated look" that you're talking about.)

RwP
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Jul 11, 2015 | 10:59 AM
  #3  
Thanks Ralph but wrong bolts. Those look to be the Y pipe to exhaust manifold bolts I'll keep them in mind for when I get that far. Here is a post I found by searching this morning; https://dodgeforum.com/forum/2nd-gen...bolt-size.html I expect I will have to remove the manifolds and then the studs to take them in to AZ to replace. Did the same thing for my intake on a Dodge Ram50. Seems like the dealer charges $32 and their fasteners have the breaking problem. That price is in a 9 year old post so it may be more now.
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Jul 11, 2015 | 10:52 PM
  #4  
The ones I put on my 1988 were also 3/8-16, but not those studs.

But I see what you mean.

RwP
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Mar 2, 2017 | 05:42 PM
  #5  
Just got through putting on the third set of RH exhaust manifold gaskets and bolts, and second exhaust manifold on my 2005 Dakota. No reason for this to happen three times in 130,000 miles. No failures on the left side. Another engineering snafu!
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Mar 2, 2017 | 08:21 PM
  #6  
Quote: Just got through putting on the third set of RH exhaust manifold gaskets and bolts, and second exhaust manifold on my 2005 Dakota. No reason for this to happen three times in 130,000 miles. No failures on the left side. Another engineering snafu!
There are many possibilities. Did you get the right studs, bolts and washers from the dealer? There are special washers for the studs, I forget what they are called but they are curved. The curve faces in to the block. The exhaust manifold may be warped and when it heats up put undo pressure on the stud or bolt.
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Mar 2, 2017 | 08:46 PM
  #7  
Bonneville washers; you can buy them from places like Mancini Racing ( http://www.manciniracing.com/maraexmacowa.html ).

RwP
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Dec 16, 2017 | 12:22 PM
  #8  
think my last reply is lost in forum cybertechspaceheaven. Anyway anybody have an opinion of migging on a threaded section to the broken stud, assuming that it is not broken flush? Good wire and Ar should be strong, bolts weren't that strong to begin with.
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Dec 16, 2017 | 12:52 PM
  #9  
Quote: think my last reply is lost in forum cybertechspaceheaven. Anyway anybody have an opinion of migging on a threaded section to the broken stud, assuming that it is not broken flush? Good wire and Ar should be strong, bolts weren't that strong to begin with.
I would think if you had enough sticking out to weld onto you could pull it to replace it. As a rule when one welds the weld is stronger than the adjoining metal and these studs are so small that much heat will destroy its temper and make it weak enough to stretch and lose hold or brittle so that it breaks again.
I have had no problems with it since I fixed mine.
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Dec 16, 2017 | 01:37 PM
  #10  
Yeah, if there is enough sticking out to weld something to, weld a nut to it, and extract it.
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