AMC Eagle Den Forum

The Mighty 258 => Exhaust System. => Topic started by: Nightpath on June 18, 2014, 09:32:51 PM

Title: Exhaust manifold bolts
Post by: Nightpath on June 18, 2014, 09:32:51 PM
I'm trying to place a missing bolt on the hard as heck to reach home by the firewall and having all sorts of fun.

Is this bolt the same size as the others?  And is there any tricks to getting it in?

So frustrated atm. Manifold had a huge leak. .. Found this bolt missing and I want to see if pouring one in will fix the problem.
Title: Re: Exhaust manifold bolts
Post by: carnuck on June 19, 2014, 01:01:41 AM
If it's the very rear one on the manifold, it's common to fall out and usually takes a piece of gasket with it. If the noise is at the 2 bolt flange, I have cut/drilled and replaced a few with nut/bolt combos. If you have the AIR pipes, they tend to burn out where you can't see them and make a ton of noise!
Title: Re: Exhaust manifold bolts
Post by: DaemonForce on June 19, 2014, 04:13:37 AM
Last I recall they're STUDS not bolts. ??? If you're missing bolts just pull one from a Cherokee.
Title: Re: Exhaust manifold bolts
Post by: Nightpath on June 19, 2014, 06:11:02 AM
So its an alignment stud is it? Threaded for a nut? There is diddly squat there.

Is it the same thread and width as the other bolts around the manifold?
Title: Re: Exhaust manifold bolts
Post by: DaemonForce on June 19, 2014, 06:33:25 AM
Yeah it is. My Eagle's 258 had the same missing stud right at the very end next to the firewall. It was causing a HUGE exhaust leak. I'm too drunk to think about this right now. Just thread in a new stud similar to the ones in your transfer case or use a bolt from a Cherokee or whatever has a 4.0L they're the same size and pattern.
Title: Re: Exhaust manifold bolts
Post by: Nightpath on June 19, 2014, 07:06:02 AM
No junkyards will let me take one around here. Going to have to get a new stud/bolt at the hardware store.

Is it different than the other manifold bolts and studs?
Title: Re: Exhaust manifold bolts
Post by: Mernsy on June 19, 2014, 08:12:09 AM
Quote from: Nightpath on June 19, 2014, 07:06:02 AM
Is it different than the other manifold bolts and studs?

Remove another bolt and try it.
Title: Re: Exhaust manifold bolts
Post by: BenM on June 19, 2014, 11:52:34 AM
They're all the same thread. Course into the block and fine for the nut, but I can't remember the pitch offhand. I try to find a slightly longer stud for that back and bottom ones so it's easier to get the nut threaded, and then I use about 3-4 short wobble extensions to reach it.

The factory didn't use an exhaust gasket, and I don't believe they always inserted that back end stud either.

Take a bolt into a good hardware store and they'll be able to sell you studs for less than a dollar a piece in a few sizes so you can see what works best for you.
Title: Re: Exhaust manifold bolts
Post by: DownwardFlame on June 19, 2014, 12:36:46 PM
Is the hole open? I've seen a lot of broken off exhaust studs on newer rigs.... Not fun, especially when they're into aluminum heads...
Title: Re: Exhaust manifold bolts
Post by: eagleman on June 19, 2014, 02:24:08 PM
The back stud was busted off in my wagon along with the front one as well. Purchased a cheap air angle drill off ebay. I removed the intake and exhaust manifold used a center punch to center punch the busted studs. Sprayed the busted studs with pb blaster then used a small drill bit and drilled a small hole through the busted studs. Never had to use a easy out as the busted studs both came out while drilling through the studs. Went to my local Chrysler Jeep dealer and ordered a new set of studs. Then went to auto zone and purchased a new intake and exhaust manifold gasket. Originally AMC didn't use a gasket just medal to medal but its wise to use a gasket before reinstalling them. Might also check your exhaust manifold for warpage as most are warped. I took mine to a auto machine shop and had it surfaced before reinstalling it. There are only two studs used. The very first one and the very back one. The rest are bolts and I purchased new grade eight bolts from Menards.
Title: Re: Exhaust manifold bolts
Post by: milliard431 on October 10, 2014, 10:56:44 AM
I noticed that in this post a few members mention the type of thread and/or grade of bolts. I wonder, as clearly some members are extremely knowledgeable, if anyone has listed the nuts and bolts for our cars by type, size and grade just like the designers would and the way that they are sold. It sounds like some members could list them off the top of their heads but we usually refer to them simply by placement or what part they secure. Although it might take some time to assemble a list I'd bet it would save a lot of posting time for the moderators. It seems that anyone who manufacture anything tries rouse as many of the same fastening systems and sizes as possible. It just makes good business sense and limits worker mistakes. Maybe there is already such a list but I don't remember one. 
Title: Re: Exhaust manifold bolts
Post by: carnuck on October 11, 2014, 02:09:33 AM
You want to check what's already there to ensure you get a match.
Title: Re: Exhaust manifold bolts
Post by: AMCLOVER258 on November 10, 2014, 07:35:30 PM
Is the nuts to the maifold like a 12mm nut? i found two sitting on my Front diff.... trying to figure out where they go to..
Title: Re: Exhaust manifold bolts
Post by: amcfool1 on March 06, 2016, 11:24:48 PM
manifold bolts are 3/8-16, two end studs are 3/8-16 into head, 3/8-24 for nut, though that last one isn't a big deal, can be 3/8-16 also, gz