Please reference https://www.f150online.com/forums/sh...d.php?t=264241 for photos from someone else's post. My driver's side flange bolts look very much like the first photo where one is gone and the other has a little hold left. My manifold bolts and nuts look fine, so I don't plan to mess with the manifold just yet, just want to fix the exhaust leak. I am thinking of drilling out the two studs and replacing them with through bolts if the studs cannot be removed. I have seen suggestions to weld a nut to the stud and turn it out that way. I don't much care if I can use studs again due to larger drilled holes in the manifold, if I can, that would be great. I am not sure if the studs are super tempered due to the heating/cooling cycles they have seen, in which case drilling might not be possible. Any suggestions on drilling out the studs while the manifold is still on the engine? What type of drill bit would you use?

If removal or drilling are not possible, I have an idea for a plate that will fit over the end of the exhaust manifold to be used as a clamping plate. Run two bolts from it to the existing flange clamp.

Thanks!
Joseph

 

The welding of a nut to the stud was for the studs going into the head.

You may be able to drill out top stud. If not they're C clamp like clamps that should hold the pipe clamp to manifold. You could use 1 or 2 per side. I've used one in the past. (AutoZone) Cost is everything, looks don't count. LOL