1997 5.4 Exhuast Flange Stud Replacement

[tinkering]

1997 Expy 5.4

The drivers side exhaust flange is leaking badly; it fills the cab with fumes . I bought it that way.

I went under and noticed one stud has rotted right off. The other stud shaft is getting mighty thin.

The passenger side studs are still holding so I might do them later unless I have to drop both sides to get at the passenger side flange.

* I assume they are studs that are threaded into the manifold side? They look so deteriorated that I am expecting to have to remove them by some means other than simply backing them out.

* I can get oxygen for my propane oxygen torch. Heat them up and shock them back with a wet cloth, then attempt to back them out with vice-grips or an extractor.

* I can drill them out IF THERE IS ROOM TO GET IN THERE?

What's the best bet?

Should I replace them with studs or just use nuts and bolts to ease the job next time?
Should I just take it in to the muffler shop and pay them to take my problem?

NB: I notice a couple of broken exhaust manifold studs; one on each bank at the rear, that I was just going to leave for the time being. I would like it back on the road without having to do that job right away too. Are these Expys notorious for rotting out like this?

 

[tcwaltz]

May be easier to pull the wheel, the wheel liner and take the exhaust manifold off the head. Granted this could lead to other work with the exhaust manifold and broken studs, but if those are rotted away chances are so are the exhaust studs.

 

[tinkering]

May be easier to pull the wheel, the wheel liner and take the exhaust manifold off the head. Granted this could lead to other work with the exhaust manifold and broken studs, but if those are rotted away chances are so are the exhaust studs.

That makes great sense but I was not planning on doing the whole nine yards. That's too much of a can of worms until I have the time needed, though I will be considering that now.
I could do just the drivers side exhaust manifold, and leave the passenger side until the flange stud lets go on that side.
Thanks

Is there room to get the drill up to the exhaust flange from underneath to drill those 2 studs out? I will go under there and see

 

[tcwaltz]

Not easily. I was using a 6 or 9" extension and deep well socket when I was reinstalling mine. There is some space to work, but as I recalls its near the frame and its just awkward. Can't imagine trying to drill with the pipe in place. The head is aluminum so I'd be concerned about putting alot of force on that trying to get the bolts out. Especially heating it up and cooling it off. The studs are small also...8mm if I recall. My drivers side manifold was fine, but the passenger side had two broken studs. The studs came out pretty easily as I recall. Although one of them was rotted pretty close to the head.

 

[tinkering]

Not easily. I was using a 6 or 9" extension and deep well socket when I was reinstalling mine. There is some space to work, but as I recalls its near the frame and its just awkward. Can't imagine trying to drill with the pipe in place. The head is aluminum so I'd be concerned about putting alot of force on that trying to get the bolts out. Especially heating it up and cooling it off. The studs are small also...8mm if I recall. My drivers side manifold was fine, but the passenger side had two broken studs. The studs came out pretty easily as I recall. Although one of them was rotted pretty close to the head.

I wonder if I could get away with dropping/moving just the driver's side of exhaust pipe out of the way enough to get at those two flange studs? ... that is assuming I can find the room to get the drill up in there.

I can and probably will go back to replace all 8/16 of the exhaust manifold studs later

I will post my developments so someone else might be able to do the quick repair if they are in a similar situation. They might like to read about it

 

[tinkering]

The other exhaust flange stud was about a match stick in width, which broke off with one slight blow of the hammer (the passenger side exhaust flange studs look new).
You are right tcwaltz, it is a tricky looking job to drill and remove the old EF stud stubs up in there but not impossible; the pipe didn't drop at all when I broke the 2nd stud off.

I checked the passenger side exhaust flange and exhaust manifold for leakage. There is a wee bit coming out of the rear port; the EF is tight.

The driver side manifold has substantial leakage out of the rear port. I think it should be changed. It's night now. I'll see how I feel about doing it tomorrow or hide behind the couch and get the muffler shop to do it

 

[whitelightning99]

How about the egr tube that screws into the exhaust manifold drivers side ??? mine looks crusty as shit even after soaking it,flaking the rust of,using compressed air and re soaking it with pb blaster,it didnt want to come loose using a decent size adjustable wrench,i have no hot wrench

 

[tcwaltz]

Probably easier to disconnect the EGR at the EGR valve and pull the exhaust manifold. I took mine to a local machine shop and they trued them up for 40 bux a peice. Cheaper than buying new ones.

Get two packs of Dorman manifold studs. One set for each side, pull them and get them trued up and reinstalled. You'll probably see the truck run better since you won't have an exhaust leak.

 

[tinkering]

How about the egr tube that screws into the exhaust manifold drivers side ??? mine looks crusty as shit even after soaking it,flaking the rust of,using compressed air and re soaking it with pb blaster,it didnt want to come loose using a decent size adjustable wrench,i have no hot wrench

Mine may have been changed; it didn't stand out as being particularly nuked. I will look again.
I don't know if I should use the fire wrench on those manifold nuts but they seem nuked. The impact socket spun on the couple of easy ones I tried.

 

[tinkering]

Probably easier to disconnect the EGR at the EGR valve and pull the exhaust manifold. I took mine to a local machine shop and they trued them up for 40 bux a peice. Cheaper than buying new ones.

Get two packs of Dorman manifold studs. One set for each side, pull them and get them trued up and reinstalled. You'll probably see the truck run better since you won't have an exhaust leak.

I expect it will run better and I wouldn't be surprised if the engine light goes out.

Are the EM nuts 1/2" or metric in Canada? I have to try a metric socket on there before I buy a metric deep impact.
I am still thinking I will have to carefully use the fire wrench some on there. The nuts and studs look fused on the EM.

I can't wait to get to the re-installation stage even if I have to buy new manifolds for some reason.
Found so far: Dorman $185.00 CAD, ATP $165.00 CAD